Search

Background: The cytoplasmic male sterility (CMS) of rice is caused by chimeric mitochondrial DNA (mtDNA) that is maternally inherited in the majority of multicellular organisms. Wild rice (Oryza rufipogon Griff.) has been regarded as an ancestral progenitor of Asian rice (Oryza sativa). To identify additional CMS sources, and explore the origin of gametophytic CMS gene, a total of 427 individuals with 17 representative populations of O. rufipogon were collected in from Dongxiang of Jiangxi Province to Sanya of Hainan Province, China, for the PCR amplification of atp6, orfH79 and B-atp6-orfH79, respectively. Results: Among 17 populations, the B-atp6-orfH79 and its variants (B-atp6-GSV) were detected in five populations (i.e. HK, GZ, PS, TL and YJ) through PCR amplification, which were divided into three haplotypes, i.e., BH1, BH2, and BH3. The BH2 haplotype was identical to B-atp6-orfH79, while the BH1 and BH3 were the novel haplotypes of B-atp6-orfH79. Combined with the high-homology sequences in GenBank, a total of 18 haplotypes have been revealed, which only could be divided into 10 haplotypes in orfH79 and its variants (GSV) section.thatbelong to 3 species (i.e. O. rufipogon, Oryza nivara and Oryza sativa) Enough haplotypes clearly demonstrate the structural characteristics of the B-atp6-orfH79 as follows: Except for the conserved sequence (671 bp) composed of B-atp6 (619 bp) and the downstream followed the B-atp6 (52 bp, DS), and GSV sequence, a rich variable sequence (VS, 176 bp) lies between the DS and GSV with 5 insertion or deletion and more than 30 single nucleotide polymorphism. Maximum likelihood analysis showed that 18 haplotypes formed three clades with high support rate. The hierarchical analysis of molecular variance (AMOVA) indicated the occurrence of variation among all populations (FST = 1; P < 0.001), which implied that the chimeric structure occurred independently. All 17 haplotypes of the orfH79 was statisticsed based on our results and the existing references, which belong to 6 species, but their genetic relationship can not be reflected through systematic analysis. 7 existed single nucleotide polymorphism in GSV section can be translated into 11 various amino acid sequences. Conclusions: In this study, the relevant populations provide diverse CMS primary sources. B-atp6 and the GSV simultaneous existence in the plant. The sequence characteristics of B-atp6-orfH79 and Maximum Likelihood analysis indicated the chimerise occur independently with consistent chimeric sites, which might help to explore the origin of rice gametophytic CMS genes in O. rufipogon.

Xinyang Maojian tea is a kind of famous roasted green tea produced in the middle of China. Ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-Q-TOF/MS)-based metabolomics coupled with multivariate statistical analyses, including principal component analysis (PCA) and hierarchical cluster analysis (HCA), were carried out in XMMJTs collected from Luoshan, Shangcheng, and Shihe Counties, respectively. Additionally, seven catechins, four flavonoids, two purine alkaloids, and gallic acid contents were determined by HPLC. Differential metabolites were selected by p-value 0.05, and fold change 1.50 or 0.66 among 745 detected metabolites in metabolomics analysis. The results showed significant (p 0.05) differences of three catechins including (-)-epicatechin, (-)-epicatechin gallate, and (-)-gallocatechin gallate, four flavonoids (i.e. quercetin, kaempferol, myricetin, and rutin), and theobromine among three various regions, and significant (p 0.05) differences of (-)-epicatechin gallate, (-)-epigallocatechin, (+)-catechin, gallic acid, and kaempferol between Shuchazao and Group cultivar. The HCA showed that, except for two samples (i.e. LS 2 and SH 2) of Shuchazao cultivar clustered together, others could be clustered completely according to production place. The 63 relevant differential metabolites could achieve the purpose of region identification through PCA. Kyoto encyclopedia of genes and genomes (KEGG) metabolic pathway analysis elaborated the impact of geographical origin and tea cultivar on physiological metabolism in tea tree. PRACTICAL APPLICATION: Ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-Q-TOF/MS)-based liquid chromatography-tendem mass spectrometry (LC-MS/MS) metabolomics coupled with multivariate statistical analyses, such as principal component analysis (PCA) and hierarchical cluster analysis (HCA), revealed 63 differential metabolites related to production place, which contributed to the region identification of Xinyang Maojian teas.

BackgroundAncient tea plantations with an age over 100 years still reserved at Mengku Town in Lincang Region of Yunan Province, China. However, the characteristic of soil chemicophysical properties and microbial ecosystem in the ancient tea plantations and their impact on tea-leaves chemical components remained unclear. Tea-leaves chemical components including amino acids, phenolic compounds and purine alkaloids, and soil chemicophysical properties including pH, cation exchange capacity (CEC), soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorous (AP) and available potassium (AK), and microbial community structure of modern and ancient tea plantations in five geographic sites (i.e. Bingdao, Baqishan, Banuo, Dongguo and Jiulong) were determined by high performance liquid chromatography (HPLC) and high-throughput sequencing, respectively. ResultsTea-leaves chemical components, soil chemicophysical properties and microbial community structures including bacterial and fungal community abundance and diversity evaluated by Chao 1 and Shannon varied with geographic location and tea plantation type. The ancient tea plantations possessed significantly (PPPConclusionsDue to the natural cultivation way, the ancient tea plantations still maintained relatively higher soil fertility and complete soil microbial ecosystem, which contributed to the sustainable development with higher quality in tea-leaves.

BackgroundAncient tea plantations with an age over 100 years still reserved at Mengku Town in Lincang Region of Yunan Province, China. However, the characteristic of soil chemicophysical properties and microbial ecosystem in the ancient tea plantations and their impact on tea-leaves chemical components remained unclear. Tea-leaves chemical components including amino acids, phenolic compounds and purine alkaloids, and soil chemicophysical properties including pH, cation exchange capacity (CEC), soil organic matter (SOM), soil organic carbon (SOC), total total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorous (AP) and available potassium (AK), and microbial community structure of modern and ancient tea plantations in five geographic sites (i.e. Bingdao, Baqishan, Banuo, Dongguo and Jiulong) were determined by high performance liquid chromatography (HPLC) and high-throughput sequencing, respectively. ResultsTea-leaves chemical components, soil chemicophysical properties and microbial community structures including bacterial and fungal community abundance and diversity evaluated by Chao 1 and Shannon varied with geographic location and tea plantation type. The ancient tea plantations possessed significantly (PPPConclusionsDue to the natural cultivation way, the ancient tea plantations still maintained relatively higher soil fertility and complete soil microbial ecosystem, which contributed to the sustainable development with higher quality in tea-leaves.

Storage environment caused the difference between Jinhua Pu‐erh tea (JPT) and General Pu‐erh tea. In this study, fungal flora and chemical compositions were analyzed. The results showed that storage environment caused significant (p, Aspergillus pallidofulvus, Aspergillus sesamicola, and Penicillium manginii selected from Pu‐erh tea were dominant fungi, which could generate macroscopic yellow cleistothecia and have specific effects on given chemical compositions after a long‐term storage. This study revealed the dominant fungi and their effects on chemical compositions during the storage of Pu‐erh tea.

Microstructure, texture and hardness evolutions of Al-Mg-Si-Cu alloy during annealing treatment were studied by microstructure, texture and hardness characterization in the present study. The experimental results show that microstructure, texture and hardness will change to some extent with the increase of annealing temperature. The microstructure transforms from the elongated bands to elongated grains first, and then the grains grow continuously. The texture transforms from the initial deformation texture b fiber to recrystallization texture mainly consisting of CubeND {001} and P {011} orientations first, and then the recrystallization texture may be enhanced continuously as a result of the grain growth. Hardness decreases slowly at first, and then decreases sharply and increases significantly finally. Besides, the particle distributions also have great changes. As the annealing temperature increases, they increase firstly as a result of precipitation, and then gradually disappear as a result of dissolution. Finally, the effect of annealing temperature on microstructure, texture and hardness evolutions is discussed.

Background Caffeine is one of the most abundant methylxanthines in tea, and it remains stable in processing of general teas. In the secondary metabolism of microorganism, theophylline is the main conversion product in caffeine catabolism through demethylation. Microorganisms, involved in the solid-state fermentation of pu-erh tea, have a certain impact on caffeine level. Inoculating an appropriate starter strain that is able to convert caffeine to theophylline would be an alternative way to obtain theophylline in tea. The purpose of this study was to isolate and identify the effective strain converting caffeine to theophylline in pu-erh tea, and discuss the optimal conditions for theophylline production. Results Caffeine content was decreased significantly (p p Aspergillus niger, Aspergillus sydowii, Aspergillus pallidofulvus, Aspergillus sesamicola and Penicillium mangini, respectively. Especially, A. pallidofulvus, A. sesamicola and P. mangini were detected in pu-erh tea for the first time. All isolates except A. sydowii TET-2, enhanced caffeine content and had no significant influence on theophylline content. In the aerobic fermentation of A. sydowii TET-2, 28.8 mg/g of caffeine was degraded, 93.18% of degraded caffeine was converted to theophylline, and 24.60 mg/g of theophylline was produced. A. sydowii PET-2 could convert caffeine to theophylline significantly, and had application potential in the production of theophylline. The optimum conditions of theophylline production in the aerobic fermentation were 1) initial moisture content of 35% (w/w), 2) inoculation quantity of 8%, and 3) incubation temperature at 35 °C. Conclusions For the first time, we find that A. sydowii PET-2 could convert caffeine to theophylline, and has the potential value in theophylline production through aerobic fermentation.

The effect of solution heating rate on quasi-static and dynamic mechanical properties of Al-Mg-Si-Cu alloy in bake hardening state was investigated through mechanical properties, microstructure and fracture morphology characterization in the present study. The results show that solution heating rate has a strong influence on microstructure, quasi-static and dynamic mechanical properties. As solution heating rate rises, the grain microstructure transforms from the elongated grains to equiaxed grains and the fraction of low-angle grain boundaries (LAGBs) also decreases. Moreover, the equivalent average grain size first decreases, and then increases. The relationship between solution heating rate and mechanical property is monotonic, not depending on strain rate. As solution heating rate rises, the yield strength, ultimate tensile strength and elongation decrease. In contrast to quasi-static loading, dynamic loading always tends to improve strengths and elongation. In addition, compared with the quasi-static tensile specimens, the dynamic tensile specimens possess a larger number of dislocations. Regardless of strain rate and solution heating rate, all the tensile specimens exhibit the ductile fracture mode. As solution rate rises, the dimples decrease and become shallow gradually. The dimples in dynamic fracture zone are larger and deeper than those in the quasi-static fracture zone.

With the aim to reveal the microbial community succession at various temperatures in the fermentation of Qingzhuan tea (QZT), the Illumina NovaSeq sequencing was carried out to analyze bacterial and fungal community structure in tea samples collected from the fermentation set at various temperatures, i.e., 25 °C, 30 °C, 37 °C, 45 °C, 55 °C, and room temperature. The results showed that fermentation temperature profoundly affected the microbial community succession in the QZT fermentation. Microbial richness and community diversity decreased along with the increase of fermentation temperature. Despite the differences between microorganisms and their metabolic types among various temperatures, most bacteria and fungi showed positive correlations at the genera level. Klebsiella, Paenibacillus, Cohnella, and Pantoea were confirmed as the main bacterial genera, and Aspergillus and Cyberlindnera were the main fungal genera in QZT fermentation. The microbial genera (i.e. Aspergillus, Rhizomucor, Thermomyces, Ralstonia, Castellaniella, and Vibrio) were positively correlated with fermentation temperature (P 0.05), while Klebsiella, Paenibacillus, and Aspergillus had good adaptability at different temperatures. Conversely, Pantoea and Cyberlindnera were only suitable for low temperature (≤37 °C) growth, and Thermomyces was only suitable for high temperature (37 °C) growth. Aspergillus had a significant positive correlation with tea aroma quality (r = 0.64, p 0.05). This study would help to understand the formation mechanism of QZT from microflora perspective.

Based on the optimization experiment of laser welding process of niobium-tungsten alloy, the effects of assembly gap value and misalignment value on laser weld formation, microstructure and mechanical properties of Nb521 niobium-tungsten alloy were investigated by using variable gap method, equal gap method and equal misalignment value method. The results show that Nb521 niobium-tungsten alloy has good laser weldability. The maximum gap value margin of 1.0mm and 1.5mm thickness of base metal are about 22% and 10.6% of the base metal thickness, respectively. And the maximum misalignment value margin is about 30% and 33% of the base metal thickness, respectively. The welded joints are characterized by fine columnar crystal structure from the fusion zone to the center of the weld, and are little affected by assembly gap value and misalignment value. When the assembly gap value or misalignment value is not greater than the maximum margin, the welded joints are fractured in the base metal zone, which is far away from the weld. Therefore, the welded joints of Nb521 niobium-tungsten alloy by laser welding have excellent tensile mechanical properties at room temperature.

For the scientific classification of Pu-erh ripened teas (PRTs), phytochemical compositions including 14 polyphenolic compounds, 2 purine alkaloids and 18 free amino acids in 24 PRTs were determined by HPLC, respectively. The in vitro antioxidant activities were evaluated by 5 various assays. PCA explaining 38.7% of total variance, HCA and OPLS-DA (R2Y = 0.887, Q2 = 0.873, respectively) could classify PRTs into Puer and Banna groups by production place basically, which caused significant (P

Contents of 20 bioactive compounds in 12 teas produced in Xinyang Region were determined by high performance liquid chromatography. Ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry was developed for untargeted metabolomics analysis. Antioxidant activities were measured by 4 various assays. Those teas could be completely divided into green and white tea through principal component analysis, hierarchical cluster analysis and orthonormal partial least squares-discriminant analysis (R2Y = 0.996 and Q2 = 0.982, respectively). The prolonged withering generated 472 differentiated metabolites between white and green tea, prompted significant decreases (variable importance in the projection > 1.0, p-value 1.50) of most catechins and 8 phenolic acids to form 4 theaflavins, and benefited for the accumulation of 17 flavonoids and flavonoid glycosides, 8 flavanone and their derivatives, 20 free amino acids, 12 sugars and 1 purine alkaloid. Additionally, kaempferol and taxifolin contributed to 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability of white tea.

Microbiota influenced quality formation of ripened Pu-erh tea. To understand the effect of each tea-derived fungal strain, tea-leaves were fermented by Aspergillus pallidofulvus PT-3 (ApaPT), Aspergillus sesamicola PT-4 (AsePT) and Penicillium manginii PT-5 (PmaPT), respectively. 14 Phenolic compounds, 3 purine alkaloids, 19 free amino acids and γ-aminobutyric acid contents were determined by HPLC and amino acid analyzer analysis. Additionally, UHPLC-Q-TOF/MS method was developed for LC-MS metabolomics analysis. Multivariate statistical analyses, such as PCA and HCA, exhibited that the chemical profile of PmaPT fermentation was similar to biocidal treatment, but had significant differences with ApaPT and AsePT fermentation. The differentiated metabolites (VIP 1, p 0.05 and FC 1.50 or 0.66) and one-way ANOVA revealed the impact of three fungal strains in tea-leaves fermentation. APaPT and AsePT contributed to biosynthesis of gallic acid and several flavonoids, such as kaempferol, quercetin and myricetin in the metabolism of phenolic compounds.

Background Methylxanthines, including caffeine, theobromine and theophylline, are natural and synthetic compounds in tea, which could be metabolized by certain kinds of bacteria and fungi. Previous studies confirmed that several microbial isolates from Pu-erh tea could degrade and convert caffeine and theophylline. We speculated that these candidate isolates also could degrade and convert theobromine through N-demethylation and oxidation. In this study, seven tea-derived fungal strains were inoculated into various theobromine agar medias and theobromine liquid mediums to assess their capacity in theobromine utilization. Related metabolites with theobromine degradation were detected by using HPLC in the liquid culture to investigate their potential application in the production of 3-methylxanthine. Results Based on theobromine utilization capacity, Aspergillus niger PT-1, Aspergillus sydowii PT-2, Aspergillus ustus PT-6 and Aspergillus tamarii PT-7 have demonstrated the potential for theobromine biodegradation. Particularly, A. sydowii PT-2 and A. tamarii PT-7 could degrade theobromine significantly (p A. sydowii PT-2 and A. tamarii PT-7 culture, respectively, which confirmed the existence of N-demethylation and oxidation in theobromine catabolism. 3-Methylxanthine was common and main demethylated metabolite of theobromine in the liquid culture. 3-Methylxanthine in A. sydowii PT-2 culture showed a linear relation with initial theobromine concentrations that 177.12 ± 14.06 mg/L 3-methylxanthine was accumulated in TLM-S with 300 mg/L theobromine. Additionally, pH at 5 and metal ion of Fe2+ promoted 3-methylxanthine production significantly (p Conclusions This study is the first to confirm that A. sydowii PT-2 and A. tamarii PT-7 degrade theobromine through N-demethylation and oxidation, respectively. A. sydowii PT-2 showed the potential application in 3-methylxanthine production with theobromine as feedstock through the N-demethylation at N-7 position.

Background Methylxanthines including caffeine, theobromine and theophylline are natural and synthetic compounds in tea. Theobromine and other methylxanthine could be metabolized by certain kinds of bacteria and fungi. Previous studies confirmed that several isolates from Pu-erh tea could degrade and convert caffeine and theophylline through N-demethylation and related oxidation, respectively. In this study, seven tea-derived fungi were inoculated into various theobromine agar mediums and liquid mediums to assess their capacity in theobromine utilization. Related metabolites with theobromine degradation were detected by using HPLC in the liquid culture inoculated by candidate isolates to investigate potential application in the production of 3-methylxanthine. Results Based on the extent of theobromine utilization, four isolates including Aspergillus niger, Aspergillus sydowii, Aspergillus ustus and Aspergillus tamarii have demonstrated the potential for theobromine biodegradation. Particularly, A. sydowii and A. tamarii could degrade theobromine significantly (p < 0.05) in all given theobromine liquid mediums. 3,7-Dimethyluric acid, 3-methylxanthine, 7-methylxanthine, 3-methyluric acid, xanthine, and uric acid were detected in A. sydowii and A. tamarii culture, respectively, confirming the existence of N-demethylation and oxidation in theobromine catabolism. 3-Methylxanthine was common and main demethylated metabolite of theobromine in A. sydowii and A. tamarii culture. 3-Methylxanthine in A. sydowii culture showed a linear relation with the initial theobromine concentrations that 177.12 ± 14.06 mg/L of 3-methylxanthine was accumulated in TLM-S with 300 mg/L of theobromine. Additionally, pH at 5 and metal ion of Fe 2+ promoted 3-methylxanthine production significantly (p < 0.05). Conclusions This study is the first to confirm that A. sydowii and A. tamarii degrade theobromine through N-demethylation and oxidation, respectively. A. sydowii showed the potential application in 3-methylxanthine production with theobromine as feedstock through the N-demethylation at position N-7.

Additional file 2: Table S1. Comparisons of fungal dry mass (mg) of each isolate in different theophylline liquid mediums after cultivation at 30 °C for 5 days. TLM-S = theophylline liquid medium with sucrose as carbon source; TLM-D = theophylline liquid medium with dextrose with sucrose as carbon source; TLM-N = theophylline liquid medium with ammonium sulphate as nitrogen source; TLM-SN = theophylline liquid medium with sucrose and ammonium sulphate as carbon and nitrogen sources, respectively. All data were present by mean value ± SD of three replications. The lowercase letters indicated a significant difference at p

Additional file 1: Figure S1. Colony characteristics (a, b) and conidial structure (c, d) of strain PT-6. (a): Front on PDA medium at 25 °C for 7 days. (b): Back on PDA medium at 25 °C for 7 days. (c): Mature conidia heads, conidia stems and antipodal cells (200 ×). (d): Hyohae, conidia stems and conidiums (400 ×). Figure S2. Colony characteristics (a, b) and conidial structure (c, d) of strain PT-7. (a): Front on PDA medium at 25 °C for 7 days. (b): Back on PDA medium at 25 °C for 7 days. (c): Conidia heads(200 ×). (d): Conidia stems, sterigmas and conidiums (400 ×). Figure S3. The received sequences of strain PT-6 (502 bp ITS sequence and 694 bp calmodulin sequence). Figure S4. The received sequences of strain PT-7 (532 bp ITS sequence,476 bp β-tubulin sequence and 715 bp calmodulin sequence). Figure S5. Neighbor-Joining consensus trees of (a) Aspergillus ustus PT-6 and (b) Aspergillus tamarii PT-7. Identification was based on ITS and calmodulin genes for A. ustus PT-6, and ITS, β-tubulin and calmodulin genes for A. tamarii PT-7. The numbers over branches represent bootstrap confidence values (%) based on 1000 replicates. The scale bar denotes the nucleotide substitution per sequence.

Background: Caffeine, theobromine and theophylline are main purine alkaloid in tea. Theophylline is the downstream metabolite and stays a very low level in Camellia sinensis. In our previous study, Aspergillus sydowii could convert caffeine into theophylline in solid-state fermentation of tea through N-demethylation. In this study, tea-derived fungi caused theophylline degradation in the solid-state fermentation. The aim of this study was isolate theophylline-degrading fungi and to investigate their application in production of methylxanthines with theophylline as feedstock through microbial conversion. Results: Of seven tea-derived fungi collected and identified by ITS, β-tubulin and calmodulin gene sequences, Aspergillus ustus, Aspergillus tamarii, Aspergillus niger and Aspergillus sydowii associated with solid-state fermentation of pu-erh tea have shown ability to degrade theophylline. A. ustus and A. tamarii could degrade theophylline highly significantly (p < 0.01) in liquid culture. 1,3-Dimethyluric acid, 3-methylxanthine, 3-methyluric acid, xanthine and uric acid were detected consecutively by HPLC in A. ustus and A. tamarii respectively. The data from absolute quantification analysis suggest that 3-methylxanthine and xanthine were main degraded metabolites in A. ustus and A. tamarii respectively. 129.48 ± 5.81 mg/L of 3-methylxanthine and 159.11 ± 10.8 mg/L of xanthine were produced by A. ustus and A. tamarii respectively in 300 mg/L of theophylline liquid medium. Conclusions: For the first time, we confirmed that isolated Aspergillus ustus, Aspergillus tamarii degrade theophylline through N-demethylation and oxidation. We were able to biologically produce 3-methylxanthine and xanthine efficiently from theophylline through a new microbial synthesis platform with A. ustus and A. tamarii as appropriate starter strains.

Asymmetric rolling (ASR) with three different deformation routes and conventional symmetric rolling (CR) were carried out in 7050 Al alloy plates, so as to study the influence of deformation route on the strain distribution, microstructural evolution and mechanical properties. The results show that the ASR process introduces much more effective strain throughout the thickness, resulting in severe deformation or microstructural evolution and improving the alloy's ductility compared to CR deformed samples, irrespective of the deformation routes. Among the three ASR deformation routes, the ASR-R process can introduce highest strains to improve the through-thickness deformation homogeneity, subsequently amount of finer subgrains can be observed in the wider shear band zones due to the intersection of shearing patterns of adjacent rolling passes. Although the strengths of the ASR-processed plates are almost similar, their tensile elongations are obviously affected by the deformation routes, especially the ASR–R route contributes to ~ 23% elongation, which would be mainly responsible by the grain refinement, homogeneous distribution of microstructure and fragmentation of coarse constituent particles.

The effect of particle size distribution on the microstructure, texture, and mechanical properties of Al–Mg–Si–Cu alloy was investigated on the basis of the mechanical properties, microstructure, and texture of the alloy. The results show that the particle size distribution influences the microstructure and the final mechanical properties but only slightly influences the recrystallization texture. After the pre-aging treatment and natural aging treatment (T4P treatment), in contrast to the sheet with a uniform particle size distribution, the sheet with a bimodal particle size distribution of large constituent particles and small dispersoids exhibits higher strength and a somewhat lower plastic strain ratio (r) and strain hardening exponent (n). After solution treatment, the sheet with a bimodal particle size distribution of large constituent particles and small dispersoids possesses a finer and slightly elongated grain structure compared with the sheet with a uniform particle size distribution. Additionally, they possess almost identical weak recrystallization textures, and their textures are dominated by CubeND {001} and P {011} orientations.

Ripened Pu-erh tea is a traditional microbial-fermented tea with multiple beneficial effects and the genus Aspergillus were considered as the dominant fungi. In this study, six Aspergillus and one Penicillium fungi, abbreviated as AniPT1, AsyPT2, ApaPT3, AsePT4, PmaPT5, AusPT6 and AtaPT7, were inoculated into sun-dried green tea-leaves for the microbial fermentation. Based on 42 chemical components belonging to several classes as polyphenols, amino acids and purine alkaloids, PCA and HCA revealed the significant differences in tea-leaves microbial fermentation of seven tea-derived fungi. Most of catechins, flavonoids and free amino acids were decreased highly significantly (p l -methionine, l -tryptophan, l -cysteine, l -histidine and γ-aminobutyric acid, and the improvement of antioxidant activity in tea-leaves after inoculated fermentation. Particularly, AsyPT2 converted caffeine into theophylline mainly. The bivariate correlation analysis confirmed the extremely significantly (p

Natural microorganisms involved in solid-state fermentation (SSF) of Pu-erh tea have a significant impact on its chemical components. Aspergillus sydowii is a fungus with a high caffeine-degrading capacity. In this work, A. sydowii was inoculated into sun-dried green tea leaves for SSF. Metabolomic analysis was carried out by using UPLC-QTOF-MS method, and caffeine and related demethylated products were determined by HPLC. The results showed that A. sydowii had a significant (P < 0.05) impact on amino acids, carbohydrates, flavonoids, and caffeine metabolism. Moreover, A. sydowii could promote the production of ketoprofen, baclofen, and tolbutamide. Along with caffeine degradation, theophylline, 3-methylxanthine, 1,7-dimethylxanthine, 1-methylxanthine, and 7-methylxanthine were increased significantly (P < 0.05) during inoculated fermentation, which showed that demethylation was the main pathway of caffeine degradation in A. sydowii secondary metabolism. The absolute quantification analysis showed that caffeine could be demethylated and converted to theophylline and 3-methylxanthine. Particularly, about 93.24% of degraded caffeine was converted to theophylline, 27.92 mg/g of theophylline was produced after fermentation. PRACTICAL APPLICATION: Aspergillus sydowii could cause caffeine degradation in Pu-erh tea solid-state fermentation and produce theophylline through the demethylation route. Using a starter strain to ferment tea leaves offers a more controllable, reproducible, and highly productive alternative for the biosynthesis of theophylline.

Additional file 2 Table S1. Changes of other main chemical compounds in the fermentation of A. sydowii PET-2.

Contents of catechins, flavonoids, purine alkaloids and amino acids in raw Pu-erh teas (RPTs) of a storage time scale below 10 years and old RPTs stored in Yunnan and Guangdong Province, were determined by HPLC. Tea quality improved highly significantly (p l -tyrosine, l -theanine, l -glutamic acid, l -asparagine and l -valine with highly significant (p l -theanine, l -asparagine, l -alanine and l -valine, and the accumulation of GA, kaempferol and quercetin. This study helps to reveal quality and chemical change rules of RPTs during the storage.

Bending behaviors during multi-pass asymmetrical rolling (ASR) process were optimized by adjusting the thickness reduction per pass (e). The bending curvature can be reduced significantly, almost closing to zero at a critical thickness reduction per pass (ec), by which the continuous multi-pass ASR process can be guaranteed. ecs were obtained by Finite element (FE) simulation firstly, then applied them to the multi-pass ASR-processing. The results show that the predicted ecs are consist well with the experimental values, which can make the ASR-processed plate exit without bending during multi-pass ASR processing. Microstructural evolution, mechanical properties and fracture toughness of symmetrical rolled (SR) and ASR-processed plates with bending behavior optimization were contrastively studied and it shows that the ASR processing can impose more severe deformation to the coarse constituent particles and matrix due to the introduction of additional shear strain, resulting in the improvement of microstructural homogeneity throughout the plate thickness. And mechanical properties and the fracture toughness of the ASR-processed flat plate are improved significantly due to less coarse constituent particles after annealing. In addition, effect of the recrystallization microstructure on the fracture toughness of T6-treated SR- and ASR-processed plates is also discussed in this study.

The influences of thickness reduction per pass (TRPP, 13–75%) on the macro-deformation, strain distribution, microstructural evolution, mechanical properties and their through-thickness uniformities of 7050 Al alloy sheets processed by a series of asymmetric rolling (ASR) are investigated using finite element (FE) and experimental methods. With decreasing TRPPs, the shear distances in rolling direction (RD) between top and bottom surfaces of rolled sheets are increased, resulting in much more shear and equivalent strains, and their homogeneous distribution throughout the thickness of ASR-processed sheets. The quantity of micro-shear bands comprising fine sub-grains with average size

Background Pu-erh tea is a traditional Chinese tea and produced by natural solid-state fermentation. Several studies show that the natural microbiota influence caffeine level in pu-erh tea. Our previous research also found that the caffeine declined significantly (p

Table S1. Heating method effects on microbial count and main chemical components of tea infusion. Note: All date are presented as mean ± SD, A-Bp

Figure S1. Colony characteristics of strain No. 5 on culture medium. Figure S2. Conidia structure of strain No.5 under optical microscope. Figure S3. Colony characteristics of strain No.1 on culture medium. Figure S4. Conidia structure of strain No.1 under optical microscope. (DOCX 3679Â kb)

Figure S5. ITS sequences data of the target strains. (DOCX 16Â kb)

The strain components (shear strain, strain in rolling direction), equivalent strain and deformation of elements through sheet thickness in symmetric / asymmetric rolled AA 7075 Al alloy sheets were quantified using finite element method (FEM) with taking into account the deformation histories. The FEM results showed that positive and negative shear strains can be formed after a single-pass rolling and the total shear strain in the middle thickness of asymmetric rolled sheet (asymmetric ratio: 1.25) can be greatly increased compared to that of symmetric rolled sheet for the introduction of severe plastic shear deformation, so as to improve the equivalent strain. Using the engraved-mark experimental method the FEM results were verified to be consistent. Moreover, it can be found that much more shear bands will be introduced through the thickness of asymmetric rolled sheet, especially in the middle layer, indicating that asymmetric rolling greatly favors to through-thickness deformation accumulation.