Effects of different over-fired drying methods on the aroma of Lu'an Guapian tea.

Over-fired drying, a crucial process in the production of Lu'an Guapian (LAGP) tea, greatly enriches the tea's aroma. In this study, the aroma compounds of LAGP tea processed through pulley charcoal drying (PCD), roller drying (RD), roller-conveyor drying (RCD), and hot air drying (HD) were analyzed using gas chromatography-mass spectrometry. A subsequent analysis of aroma extraction dilution analysis and odor activity values revealed that (E)-ß-ionone, dimethyl sulfide, (E,E)-2,4-heptadienal, geraniol, linalool, benzeneacetaldehyde, coumarin, 2-ethyl-3,5-dimethyl-pyrazine, indole, hexanal, (Z)-jasmone, and (Z)-3-hexen-1-ol were the key contributors to the samples' aroma variation. Moreover, a quantitative descriptive analysis and aroma recombination and omission experiments analysis revealed that (E)-ß-ionone is the most critical contributor to the formation of floral aroma in tea processed using PCD, whereas (E,E)-2,4-heptadienal is responsible for the more pronounced fresh aroma in tea processed using HD. In addition, 2-ethyl-3,5-dimethyl-pyrazine contributes to the formation of a roasted aroma in tea processed using RD and RCD. The study results provide a theoretical basis for choosing the processing method, especially for drying, to obtain high-quality LAGP tea.

Metabolomics analysis reveals the mechanism underlying the improvement in the color and taste of yellow tea after optimized yellowing.

In this study, an optimized yellowing process for yellow tea (YT) was developed by response surface methodology. The results showed that increasing the yellowing temperature from 20 °C to 34 °C, increasing the relative humidity from 55% to 67%, and reducing the yellowing time from 48 h to 16 h, caused a 40.5% and 43.2% increase in the yellowness and sweetness of YT, respectively, and improved the consumer acceptability by 36.8%. Moreover, metabolomics was used to explore the involved mechanisms that resulted in the improved YT quality. The optimized yellowing promoted the hydrolysis of 5 gallated catechins, 6 flavonoid glycosides, theogallin and digalloylglucose, resulting in the accumulation of 5 soluble sugars and gallic acid. Meanwhile, it promoted the oxidative polymerization of catechins (e.g., theaflagallin, δ-type dehydrodicatechin and theasinensin A), but decelerated the degradation of chlorophylls. Overall, this optimized yellowing process could serve as a guide to a shorter yellowing cycle.

Revelation of volatile contributions in green teas with different aroma types by GC-MS and GC-IMS.

Aroma types of green teas associate with their commercial prices and consumer acceptance, mainly including floral-like (HX), chestnut-like (LX), and fresh (QX) aromas. However, the volatile differences and specificities in these aroma types are still unclear. Herein, Taiping Houkui green teas with HX, LX, and QX aromas were processed separately with the same fresh tea leaves. Ninety-four and seventy-eight volatiles were detected and identified by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), respectively. Candidate differential volatiles among the tea samples were determined by the variable importance in projection (VIP) of the partial least squares-discriminant analysis (PLS-DA) and were further confirmed by the relative odor activity value (ROAV) and odor description. The volatiles 1-hexanol, linalool oxide (furanoid), linalool, geraniol, (E)-ß-ionone, isoamyl acetate, and 2-methylpropanal enriched in HX and contributed to the floral-like aroma, while 3-methylbutanal, 2-ethyl-1-hexanol, indole, ß-damascone, and cedrol enriched in LX and contributed to the chestnut-like aroma. This study reveals the specificities and contributions of volatiles in green teas with different aromas, thus providing new insights into the molecular basis of different flavored teas, benefiting for their precision processing and targeted quality control.

Monitoring green tea fixation quality by intelligent sensors: comparison of image and spectral information.

BACKGROUND: Intelligent monitoring of fixation quality is a prerequisite for automated green tea processing. To meet the requirements of intelligent monitoring of fixation quality in large-scale production, fast and non-destructive detection means are urgently needed. Here, smartphone-coupled micro near-infrared spectroscopy and a self-built computer vision system were used to perform rapid detection of the fixation quality in green tea processing lines. RESULTS: Spectral and image information from green tea samples with different fixation degrees were collected at-line by two intelligent monitoring sensors. Competitive adaptive reweighted sampling and correlation analysis were employed to select feature variables from spectral and color information as the target data for modeling, respectively. The developed least squares support vector machine (LS-SVM) model by spectral information and the LS-SVM model by image information achieved the best discriminations of sample fixation degree, with both prediction set accuracies of 100%. Compared to the spectral information, the image information-based support vector regression model performed better in moisture prediction, with a correlation coefficient of prediction of 0.9884 and residual predictive deviation of 6.46. CONCLUSION: The present study provided a rapid and low-cost means of monitoring fixation quality, and also provided theoretical support and technical guidance for the automation of the green tea fixation process. © 2022 Society of Chemical Industry.

Evaluation of the effects of solar withering on nonvolatile compounds in white tea through metabolomics and transcriptomics.

The mechanism through which solar withering (SW) affects the quality of white tea is unclear. To address this gap in the literature, in this study, we used metabolomics and transcriptomics to investigate the effect of SW on the quality of WT. WT that underwent SW was slightly more bitter and astringent than WT that underwent natural withering (control group). Specifically, SW considerably increased the concentration of astringent flavonoids and flavone glycosides in WT. This increase was mainly attributed to the upregulated expression of key genes in the shikimic acid, phenylpropanoid, and flavonoid biosynthesis pathways, such as shikimate kinase, chalcone synthase, and flavonol synthase. In addition, SW experienced considerable heat and light stress. The levels of glycerophosphatidylcholine and carbohydrates increased in response to the stress, which also affected the taste of WT. The results of this study indicate the mechanism through which SW affects the quality of WT.

Effects of Dietary Quinoa Seeds on Cecal Microorganisms and Muscle Fatty Acids of Female Luhua Chickens.

To study the effects of adding quinoa seed (raw grain) to the diet of the Luhua chicken on the cecal microorganism abundance and fatty acid composition of muscle, 120 49-day-old healthy female dewormed Luhua chickens (body weight 1476.21 ± 101.39 g) were randomly divided into 4 groups, with 3 replicates in each group and 10 chickens in each repetition. The control group (CK group) was fed a basal diet and the experimental groups were fed with 4% (Q4), 8% (Q8), and 12% (Q12) quinoa seed (raw grain) added to the basal diet for 75 days. After 121 days of age, the animals were slaughtered and the 16S rRNA characteristics of cecal flora, as well as composition and content of fatty acids in muscle, were determined and analyzed. The content of unsaturated fatty acids (UFAs), docosahexaenoic acid (C22:6n3; DHA) and n-3 polyunsaturated fatty acids (n-3 PUFAs) in the breast and leg muscles significantly increased in the experimental groups supplemented with quinoa seeds (p < 0.05). However, the content of saturated fatty acids (SAFs) and ratio of n-6/n-3 in breast muscle and leg muscle significantly decreased (p < 0.05). In addition, adding a certain percentage of quinoa seeds in the diet can also affect the community composition and content of microorganisms in the ceca of Luhua chickens. At the phylum level, the Proteobacteria, Actinobacteria, Synergistetes and Melainabacteria in experimental groups (Q4, Q8 and Q12) were significantly lower than those in the CK group (p < 0.05). At the genus level, Desulfovibrio, Synergistes, Olsenella, Parabacteroides, Mailhella, Sutterella and Ruminiclostridiu in group Q4 were significantly lower than those in group CK (p < 0.05) while Faecalibacterium in Q8 group, and Lawsonia and Faecalibacterium in Q12 group were significantly higher than those in the CK group (p < 0.05). Enrichment analysis of the microbial function showed that compared with the CK group, Metabolism and Enzyme Families were significantly enriched in the Q4 group (p < 0.05). Cellular Processes and Signaling were significantly enriched in the Q8 group (p < 0.05). The association analysis of fatty acids with microorganisms showed that the abundance of Faecalibacterium, Lawsonia and Meagmonas was significantly correlated with partial SFAs and UFAs (p < 0.05). In conclusion, adding quinoa seeds to diets significantly increased the content of muscle DHA, UFAs and n-3 PUFAs. The content of SAFs and the n-6/n-3 ratio were significantly reduced. Taken together, quinoa can effectively improve the cecal microbiota structure, inhibit the number of harmful bacteria and increase the number of beneficial bacteria, regulating the intestinal environment and promoting the body health of female Luhua chickens.

Effects of Microbial Action and Moist-Heat Action on the Nonvolatile Components of Pu-Erh Tea, as Revealed by Metabolomics.

Microbial action and moist-heat action are crucial factors that influence the piling fermentation (PF) of Pu-erh tea. However, their effects on the quality of Pu-erh tea remain unclear. In this study, the effects of spontaneous PF (SPPF) and sterile PF (STPF) on the chemical profile of Pu-erh tea were investigated for the first time, and sun-dried green tea was used as a raw material to determine the factors contributing to the unique quality of Pu-erh tea. The results indicated that the SPPF-processed samples had a stale and mellow taste, whereas the STPF-processed samples had a sweet and mellow taste. Through metabolomics-based analysis, 21 potential markers of microbial action (including kaempferol, quercetin, and dulcitol) and 10 potential markers of moist-heat action (including ellagic acid, ß-glucogallin, and ascorbic acid) were screened among 186 differential metabolites. Correlation analysis with taste revealed that metabolites upregulated by moist-heat and microbial action were the main factors contributing to the staler mellow taste of the SPPF-processed samples and the sweeter mellow taste of the STPF-processed samples. Kaempferol, quercetin, and ellagic acid were the main active substances formed under microbial action. This study provides new knowledge regarding the quality formation mechanism of Pu-erh tea.

Improving the flavor of summer green tea (Camellia sinensis L.) using the yellowing process.

Summer green tea (SGT) has poor flavor due to its high levels of bitterness and astringency. The present study aimed to improve the flavor of SGT using the yellowing process. The results showed that after the yellowing process, the sweetness and overall acceptability increased, and the content of gallated catechins and flavonol glycosides decreased by 30.2% and 27.4%, respectively, as did the bitterness and astringency of SGT. Yellowing caused a decrease in the concentration of some aroma compounds, such as (z)-3-hexen-1-ol, 1-hexanol, pentanal, heptanal and 1-octanol, which caused grassy, floral and fruity aromas. In contrast, the concentrations of 1-octen-3-ol, benzene acetaldehyde and ß-ionone increased, which have mushroom and sweet aromas. Meanwhile, the sweetness and umami of SGT were enhanced by the addition of selected aroma compounds (1-octen-3-ol, benzene acetaldehyde and ß-ionone), demonstrating that the yellowing process improves the flavor of SGT through odor-taste interactions.

Quality chemical analysis of crush-tear-curl (CTC) black tea from different geographical regions based on UHPLC-Orbitrap-MS.

Crush-tear-curl (CTC) black tea is a popular beverage, owing to its unique taste characteristics and health benefits. However, differences in the taste quality and chemical profiles of CTC black tea from different geographical regions remain unclear. In this study, 28 CTC black tea samples were collected from six geographical regions and analyzed using electronic tongue and ultrahigh performance liquid chromatography-Orbitrap-mass spectroscopy. The e-tongue analysis indicated that each region's CTC black tea has its own relatively prominent taste characteristics: Sri Lanka (more umami and astringent), North India (more umami), China (more sweetness and astringent), South India (moderate umami and sweetness), and Kenya (moderate umami and astringent). Based on multivariate statistical analysis, 78 metabolites were tentatively identified and used as potential markers for CTC black tea of different origins, mainly including amino acids, flavone/flavonol glycosides, and pigments. Different metabolites, which contributed to the taste characteristics of CTC black tea, were clarified by partial least squares regression correlation analysis. Our findings may serve as useful references for future studies on origin traceability and quality characteristic determination of CTC black teas. PRACTICAL APPLICATION: This study provides useful references for future studies on the origin traceability and taste characteristic determination of CTC black teas from different geographical regions.

Selenium and anthocyanins share the same transcription factors R2R3MYB and bHLH in wheat.

Anthocyanins and selenium have vital biological functions for human and plants, they were investigated thoroughly and separately in plants. Previous studies indicated pigmented fruits and vegetables had higher selenium concentration, but whether there is a relationship between anthocyanins and selenium is unclear. In this study, a combined phenotypic and genotypic methodological approach was undertaken to explore the potential relationship between anthocyanins and selenium accumulation by using phenotypic investigation and RNA-seq analysis. The results showed that pigmented cultivars enrichment in Se is a general phenomenon observed for these tested species, this due to pigmented cultivars have higher Se efficiency absorption. Se flow direction mainly improve concentration of S-rich proteins of LMW-GS. This may be a result of the MYB and bHLH co-regulate anthocyanins biosynthesis and Se metabolism at the transcriptional level. This thesis addresses a neglected aspect of the relevant relationship between anthocyanins and selenium.

Phenotypic and genetic variation in phosphorus-deficiency-tolerance traits in Chinese wheat landraces.

BACKGROUND: Phosphorus deficiency is a major limiting factors for affecting crop production globally. To understand the genetic variation of phosphorus-deficiency-tolerance, a total of 15 seedling traits were evaluated among 707 Chinese wheat landraces under application of phosphorus (AP) and non-application of phosphorus (NP). A total of 18,594 single-nucleotide polymorphisms and 38,678 diversity arrays technology sequencing markers were used to detect marker-trait associations under AP and NP. RESULTS: Top ten genotypes with extremely tolerance and bottommost ten genotypes with extremely sensitivity were selected from 707 Chinese wheat landraces for future breeding and genetic analysis. A total of 55 significant markers (81 marker-trait associations) for 13 traits by both CMLM and SUPER method. These were distributed on chromosomes 1A, 1B, 2A, 2B, 2D, 3A, 4B, 5A, 5B, 6A, 6B, 6D, 7A and 7B. Considering the linkage disequilibrium decay distance, 25 and 12 quantitative trait loci (QTL) were detected under AP and NP, respectively (9 QTL were specific to NP). CONCLUSIONS: The extremely tolerant landraces could be used for breeding phosphorus-deficiency-tolerant cultivars. The QTL could be useful in wheat breeding through marker-assisted selection. Our findings provide new insight into the genetic analysis of P-deficiency-tolerance, and will be helpful for breeding P-deficiency-tolerant cultivars.

Qualitative and quantitative diagnosis of nitrogen nutrition of tea plants under field condition using hyperspectral imaging coupled with chemometrics.

BACKGROUND: Rapid and accurate diagnosis of nitrogen (N) status in field crops is of great significance for site-specific N fertilizer management. This study aimed to evaluate the potential of hyperspectral imaging coupled with chemometrics for the qualitative and quantitative diagnosis of N status in tea plants under field conditions. RESULTS: Hyperspectral data from mature leaves of tea plants with different N application rates were preprocessed by standard normal variate (SNV). Partial least squares discriminative analysis (PLS-DA) and least squares-support vector machines (LS-SVM) were used for the classification of different N status. Furthermore, partial least squares regression (PLSR) was used for the prediction of N content. The results showed that the LS-SVM model yielded better performance with correct classification rates of 82% and 92% in prediction sets for the diagnosis of different N application rates and N status, respectively. The PLSR model for leaf N content (LNC) showed excellent performance, with correlation coefficients of 0.924, root mean square error of 0.209, and residual predictive deviation of 2.686 in the prediction set. In addition, the important wavebands of the PLSR model were interpreted based on regression coefficients. CONCLUSION: Overall, our results suggest that the hyperspectral imaging technique can be an effective and accurate tool for qualitative and quantitative diagnosis of N status in tea plants. © 2019 Society of Chemical Industry.

Metabolomics Based on UHPLC-Orbitrap-MS and Global Natural Product Social Molecular Networking Reveals Effects of Time Scale and Environment of Storage on the Metabolites and Taste Quality of Raw Pu-erh Tea.

Raw Pu-erh tea (RPT) needs ageing before drinking. However, the influence from environment and time of storage on chemical profile and flavor of RPT is unclear. In this study, the RPTs stored in wet-hot or dry-cold environment for 1-9 years were assessed using metabolomics based on UHPLC-Orbitrap-MS and global natural product social (GNPS) feature-based molecular networking as well as electronic tongue measurement. The results exhibited that the chemical profiles of RPTs were similar at an early stage but started to differentiate from each other at the 5th and the 7th year in wet-hot and dry-cold environments. The discriminating features including N-ethyl-2-pyrrolidinone-substituted flavan-3-ols (flavoalkaloids), unsaturated fatty acids, lysophosphatidylcholines, flavan-3-ols, amino acids, and flavonol-O-glycosides among the three chemical profiles were discovered and analyzed by means of multivariate statistics, GNPS multilibraries matching, and SIRIUS calculation. The metabolomic data were consistent with the results obtained through electronic tongue measurement.

Geographical origin traceability of Keemun black tea based on its non-volatile composition combined with chemometrics.

BACKGROUND: Non-volatile compounds play a key role in the quality and price of Keemun black tea (KBT). The non-volatile compounds in KBT samples from different producing areas normally vary greatly. The development of rapid methods for tracing the geographical origin of KBT is useful. In this study, we develop models for the discrimination of KBT's geographical origin based on non-volatile compounds. RESULTS: Seventy-two KBT samples were collected from five towns in Anhui province to determine 13 KBT compounds by high-performance liquid chromatography (HPLC). Analysis of variance showed that the content of 13 compounds in KBT indicated significant differences (P < 0.05) among five towns. Three multivariate statistical models including principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), and linear discriminant analysis (LDA) were built to discriminate origin. Principal component analysis effectively extracted three principal components, namely theaflavins, galloylated catechins, and simple catechins. The high sensitivity (64.5%-99.2%) was achieved of SIMCA model. To establish the discriminant functions, six variables (gallic acid, (+)-catechin, (-)-epigallocatechin gallate, theaflavin-3-gallate, theaflavin-3,3'-di-gallate, and total theaflavins) were chosen from 13 variables, and LDA was applied. This gave a satisfactory overall correct classification rate (94.4%) and cross-validation rate (88.9%) for KBT samples. CONCLUSION: The results showed that HPLC analysis together with chemometrics is a reliable approach for tracing KBT and guaranteeing its authenticity. © 2019 Society of Chemical Industry.

Quantitative trait loci analysis of root traits under phosphorus deficiency at the seedling stage in wheat.

Deficiency of available phosphorus (P) in soil limits wheat production and creates a need to develop P-deficiency-tolerant cultivars. Plant roots, important organs for absorbing nutrients and synthesizing growth regulators, are good candidates for P-efficiency screening. In this study, we evaluated five root traits under hydroponic culture conditions either with (AP) or without (NP) applied P in a recombinant inbred line population (H461/CM107) of Triticum aestivum L. at the seedling stage. Four significant quantitative trait loci (QTL) were detected, on chromosomes 1D, 2D, 3D, and 7D in NP-treated plants, explaining up to 13.0%, 11.0%, 14.4%, and 12.8% of the phenotypic variance, respectively. Among these QTL, Qrt.sicau-3D and Qrt.sicau-7D showed pleiotropic and additive effects. All QTL were found to be novel. The diversity array technology markers flanking the QTL were converted to simple sequence repeat markers that can be deployed in future genetic studies of P deficiency. These QTL lead to an increase in root biomass and respond to P-deficiency stress; these characteristics are crucial to improve root traits for breeding or further investigation of the gene(s) involved in P-deficiency tolerance.

Identification of major quantitative trait loci for root diameter in synthetic hexaploid wheat under phosphorus-deficient conditions.

Synthetic hexaploid wheat (SHW) possesses numerous genes for resistance to stress, including phosphorus (P) deficiency. Root diameter (RDM) plays an important role in P-deficiency tolerance, but information related to SHW is still limited. Thus, the objective of this study was to investigate the genetic architecture of RDM in SHW under P-deficient conditions. To this end, we measured the RDM of 138 F9 recombinant inbred lines derived from an F2 population of a synthetic hexaploid wheat line (SHW-L1) and a common wheat line (Chuanmai32) under two P conditions, P sufficiency (PS) and P deficiency (PD), and mapped quantitative trait loci (QTL) for RDM using an enriched high-density genetic map, containing 120,370 single nucleotide polymorphisms, 733 diversity arrays technology markers, and 119 simple sequence repeats. We identified seven RDM QTL for P-deficiency tolerance that individually explained 11-14.7% of the phenotypic variation. Five putative candidate genes involved in root composition, energy supply, and defense response were predicted. Overall, our results provided essential information for cloning genes related to P-deficiency tolerance in common wheat that might help in breeding P-deficiency-tolerant wheat cultivars.

Characterization and expression analyses of the H⁺-pyrophosphatase gene in rye.

The H⁺-pyrophosphatase (H⁺-PPase) gene plays an important role in maintaining intracellular proton gradients. Here, we characterized the full-length complementary DNA (cDNA) and DNA of the H⁺-PPase gene ScHP1 in rye (Secale cereale L. 'Qinling'). We determined the subcellular localization of this gene and predicted the corresponding protein structure. We analysed the evolutionary relationship between ScHP1 and H⁺-PPase genes in other species, and did real-time quantitative polymerase chain reaction to explore the expression patterns of ScHP1 in rye plants subjected to N, P and K deprivation and to cold, high-salt and drought stresses. ScHP1 cDNA included a 2289 bp open reading frame (ORF) encoding 762 amino acid residues with 14 transmembrane domains. The genomic ScHP1 DNA was 4354 bp and contained eight exons and seven introns. ScHP1 was highly homologous with other members of the H⁺-PPase gene family. When the full-length ORF was inserted into the expression vector pA7-YFP, the fluorescent microscopy revealed that ScHP1-YFP fusion protein was located in the plasma membrane. Rye plants that were subjected to N deprivation, cold and high-salt stresses, ScHP1 expression was higher in the leaves than roots. Conversely, plants subjected to P and K deprivation and drought stress, ScHP1 expression was higher in the roots than leaves. Under all the investigated stress conditions, expression of ScHP1 was lower in the stem than in the leaves and roots. Our results imply that ScHP1 functions under abiotic stress response.

Genome-wide association study of phosphorus-deficiency-tolerance traits in Aegilops tauschii.

KEY MESSAGE: Using GWAS, 13 significant SNPs distributed on six of the seven Aegilops tauschii chromosomes (all but 5D) were identified, and several candidate P-deficiency-responsive genes were proposed from searches of public databases. Aegilops tauschii, the wheat (Triticum aestivum) D-genome progenitor, possesses numerous genes for stress resistance, including genes for tolerance of phosphorus (P) deficiency. Investigation of the genetic architecture of A. tauschii will help in developing P-deficiency-tolerant varieties of wheat. We evaluated nine traits in a population of 380 A. tauschii specimens under conditions with and without P application, and we performed genome-wide association studies for these traits using single nucleotide polymorphism (SNP) chips containing 7185 markers. Using a general linear model, we identified 119 SNPs that were significantly associated with all nine traits, and a mixed linear model revealed 18 SNPs associated with all traits. Both models detected 13 significant markers distributed on six of the seven A. tauschii chromosomes (all but 5D). Searches of public databases revealed several candidate/flanking genes related to P-deficiency tolerance. These genes were grouped in five categories by the types of proteins they encoded: defense response proteins, enzymes, promoters and transcription factors, storage proteins, or proteins triggered by P deficiency. The identified SNPs and genes contain essential information for cloning genes related to P-deficiency tolerance in A. tauschii and wheat, and they provide a foundation for breeding P-deficiency tolerant wheat cultivars.

Pelitinib (EKB-569) targets the up-regulation of ABCB1 and ABCG2 induced by hyperthermia to eradicate lung cancer.

BACKGROUND AND PURPOSE: Pelitinib is a potent irreversible EGFR TK inhibitor currently in clinical trials for the treatment of lung cancer. Hyperthermia has been applied concomitantly with chemotherapy and radiotherapy to enhance treatment outcome. In this study, we investigated the ability of the combination of pelitinib with other conventional anticancer drugs to specifically target cancer cells with up-regulated efflux transporters ABCB1/ABCG2 after hyperthermia as a novel way to eradicate the cancer stem-like cells responsible for cancer recurrence. EXPERIMENTAL APPROACH: Alterations in intracellular topotecan accumulation, the efflux of fluorescent probe substrates, expression and ATPase activity of ABCB1/ABCG2 and tumoursphere formation capacity of side population (SP) cells sorted after hyperthermia were examined to elucidate the mechanism of pelitinib-induced chemosensitization. KEY RESULTS: While pelitinib did not modulate ABCB1/ABCG2 expressions, the combination of pelitinib with transporter substrate anticancer drugs induced more marked apoptosis, specifically in cells exposed to hyperthermia. The flow cytometric assay showed that both ABCB1- and ABCG2-mediated drug effluxes were significantly inhibited by pelitinib in a concentration-dependent manner. The inhibition kinetics suggested that pelitinib is a competitive inhibitor of ABCB1/ABCG2, which is consistent with its ability to stimulate their ATPase activity. SP cells sorted after hyperthermia were found to be more resistant to anticancer drugs, presumably due to the up-regulation of ABCB1 and ABCG2. Importantly, pelitinib specifically enhanced the chemosensitivity but reduced the tumoursphere formation capacity of these SP cells. CONCLUSIONS AND IMPLICATIONS: This study demonstrated a novel approach, exploiting drug resistance, to selectively kill cancer stem-like cells after hyperthermia.

[Isozymes variations among the germplasm resources of Houttuynia in Sichuan].

The peroxidase and esterase isozymes of the germplasm resources of Houttuynia in Sichuan were analyzed. The results showed that it existed plentiful isozymes variations among the germplasm resources of Houttuynia in Sichuan. The cultivated populations had the same isozymes band types as the wild ones. There were 6 different types of peroxidase isozymes bands and 10 different esterase isozymes band totally. Each peroxidase band type was composed of 4 to 6 bands, and esterase isozymes had 5 to 8 bands. There was no significant difference between Houttuynia cordata and Houttuynia emeiensis populations in their isozymes bands types. The results also showed that the number of peroxidase isozymes bands in northern areas was somewhat higher than that in southern areas. However, esterase isozymes band types had no geographic differences.