Potential structure-function relationships of pectic polysaccharides from quinoa microgreens: Impact of various esterification degrees.

Pectic polysaccharides are one of the most vital functional ingredients in quinoa microgreens, which exhibit numerous health-promoting benefits. Nevertheless, the detailed information about the structure-function relationships of pectic polysaccharides from quinoa microgreens (QMP) remains unknown, thereby largely restricting their applications as functional foods or fortified ingredients. Therefore, to unveil the possible structure-function relationships of QMP, the mild alkali de-esterification was utilized to modify QMP, and then the correlations of esterification degrees of native and modified QMPs to their biological functions were systematically investigated. The results showed that the modified QMPs with different esterification degrees were successfully prepared by the mild alkali treatment, and the primary chemical structure (e.g., compositional monosaccharides and glycosidic linkages) of the native QMP was overall stable after the de-esterified modification. Furthermore, the results revealed that the antioxidant capacity, antiglycation effect, prebiotic potential, and immunostimulatory activity of the native QMP were negatively correlated to its esterification degree. In addition, both native and modified QMPs exerted immunostimulatory effects through activating the TLR4/NF-κB signaling pathway. These results are conducive to unveiling the precise structure-function relationships of QMP, and can also promote its applications as functional foods or fortified ingredients.

Impacts of ultrasound-assisted Fenton degradation and alkaline de-esterification on structural properties and biological effects of pectic polysaccharides from Tartary buckwheat leaves.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) leaf has abundant rhamnogalacturonan-I enriched pectic polysaccharides, which exert various health-promoting effects. Nevertheless, the potential relationship between the chemical structure and the biological function of pectic polysaccharides from Tartary buckwheat leaves (TBP) remains unclear. Therefore, to bridge the gap between the chemical structure and the biological function of TBP, the impacts of ultrasound-assisted Fenton degradation (UFD) and mild alkaline de-esterification (MAD) on structural properties and biological effects of TBP were systematically studied. Compared with the native TBP (molecular mass, 9.537 × 104 Da), the molecular masses of degraded TBPs (TBP-MMW, 4.811 × 104 Da; TBP-LMW, 2.101 × 104 Da) were significantly reduced by the UFD modification, while their primary chemical structures were overall stable. Besides, compared with the native TBP (esterification degree, 22.73 %), the esterification degrees of de-esterified TBPs (TBP-MDE, 14.27 %; TBP-LDE, 6.59 %) were notably reduced by the MAD modification, while their primary chemical structures were also overall stable. Furthermore, the results revealed that both UFD and MAD modifications could significantly improve the antioxidant, antiglycation, and immunostimulatory effects of TBP. Indeed, TBP's biological effects were negatively correlated to its molecular mass and esterification degree, while positively linked to its free uronic acids. The findings demonstrate that both UFD and MAD modifications are promising techniques for the structural modification of TBP, which can remarkedly promote its biological effects. Besides, the present results are conducive to better understanding TBP's structure-bioactivity relationship.

Efficient and Selective Extraction of Rhamnogalacturonan-I-Enriched Pectic Polysaccharides from Tartary Buckwheat Leaves Using Deep-Eutectic-Solvent-Based Techniques.

Tartary buckwheat green leaves are considered to be among the most important by-products in the buckwheat industry. Although Tartary buckwheat green leaves are abundant in pectic polysaccharides, their potential applications in the food industry are quite scarce. Therefore, to promote their potential applications as functional or fortified food ingredients, both deep-eutectic-solvent-assisted extraction (DESE) and high-pressure-assisted deep eutectic solvent extraction (HPDEE) were used to efficiently and selectively extract pectic polysaccharides from Tartary buckwheat green leaves (TBP). The results revealed that both the DESE and HPDEE techniques not only improved the extraction efficiency of TBP but also regulated its structural properties and beneficial effects. The primary chemical structures of TBP extracted using different methods were stable overall, mainly consisting of homogalacturonan and rhamnogalacturonan-I (RG-I) pectic regions. However, both the DESE and HPDEE methods could selectively extract RG-I-enriched TBP, and the proportion of the RG-I pectic region in TBP obviously improved. Additionally, both the DESE and HPDEE methods could improve the antioxidant and anti-glycosylation effects of TBP by increasing its proportion of free uronic acids and content of bound polyphenolics and reducing its molecular weight. Moreover, both the DESE and HPDEE methods could partially intensify the immunostimulatory effect of TBP by increasing its proportion of the RG-I pectic region. These findings suggest that DES-based extraction techniques, especially the HPDEE method, can be promising techniques for the efficient and selective extraction of RG-I-enriched TBP.

[Selection and validation of reference genes for quantitative real-time PCR analysis in Paeonia veitchii].

Paeonia veitchii and P. lactiflora are both original plants of the famous Chinese medicinal drug Paeoniae Radix Rubra in the Chinese Pharmacopoeia. They have important medicinal value and great potential in the flower market. The selection of stable and reliable reference genes is a necessary prerequisite for molecular research on P. veitchii. In this study, two reference genes, Actin and GAPDH, were selected as candidate genes from the transcriptome data of P. veitchii. The expression levels of the two candidate genes in different tissues(phloem, xylem, stem, leaf, petiole, and ovary) and different growth stages(bud stage, flowering stage, and dormant stage) of P. veitchii were detected using real-time fluorescence quantitative technology(qRT-PCR). Then, the stability of the expression of the two reference genes was comprehensively analyzed using geNorm, NormFinder, BestKeeper, ΔCT, and RefFinder. The results showed that the expression patterns of Actin and GAPDH were stable in different tissues and growth stages of P. veitchii. Furthermore, the expression levels of eight genes(Pv-TPS01, Pv-TPS02, Pv-CYP01, Pv-CYP02, Pv-CYP03, Pv-BAHD01, Pv-UGT01, and Pv-UGT02) in different tissues were further detected based on the transcriptome data of P. veitchii. The results showed that when Actin and GAPDH were used as reference genes, the expression trends of the eight genes in different tissues of P. veitchii were consistent, validating the reliability of Actin and GAPDH as reference genes for P. veitchii. In conclusion, this study finds that Actin and GAPDH can be used as reference genes for studying gene expression levels in different tissues and growth stages of P. veitchii.

Expression patterns of cluster of differentiation 147 impact the prognosis of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) has very low overall survival. According to global cancer statistics, approximately 905677 new cases were reported in 2020, with at least 830180 of them being fatal. Cluster of differentiation 147 (CD147) is a novel, transmembrane glycoprotein that is expressed in a wide variety of tumor cells and plays an important role in various stages of tumor development. Based on the reports described previously, we theorize that CD147 may be used as a novel biological indicator to predict the prognosis of HCC. To study this possibility, expression profiles of CD147 and corresponding clinical data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were analyzed, and a hazard ratio (HR) was established. AIM: To explore the pattern of CD147 expression and its applicability in the prognosis of HCC. To establish HRs and probability points for predicting the prognosis of HCC by correlating CD147 expression with clinical characteristics. To determine if CD147 can be a reliable biomarker in HCC prognosis. METHODS: The CD147 expression profile in HCC and corresponding clinical data were obtained from TCGA database. The expression patterns of CD147 were then validated by analyzing data from the GEO database. In addition, CD147 immunohistochemistry in HCC was obtained from the Human Protein Atlas. CD147 expression patterns and clinical characteristics in the prognosis of HCC were analyzed by accessing the UALCAN web resource. Accuracy, sensitivity, and specificity of the CD147 expression profile in predictive prognosis were determined by the time-dependent receiver operating characteristic (ROC) curves. Kaplan-Meier curves were plotted to estimate the HR of survival in HCC. Univariate and multivariate Cox regression proportional hazards analyses of CD147 expression levels and clinical characteristics as prognostic factors of HCC were performed. Nomograms were used to establish probability points and predict prognosis. RESULTS: Data from TCGA and GEO databases revealed that CD147 was significantly overexpressed in HCC (P = 1.624 × 10-12 and P = 1.2 × 10-5, respectively). The expression of CD147 and prognosis of HCC were significantly correlated with the clinical characteristics of HCC as per the data from the UALCAN web resource (P < 0.05). Kaplan-Meier analysis of CD147 expression in HCC revealed that the high expression groups showed poor prognosis and an HR of survival > 1 [log-rank test, P = 0.000542, HR (in high expression group): 1.856, 95% confidence interval (CI): 1.308 to 2.636]. ROC curves were plotted to analyze the 1-year, 3-year, and 5-year survival rates. The area under the ROC curve values were 0.675 (95%CI: 0.611 to 0.740), 0.623 (95%CI: 0.555 to 0.692), and 0.664 (95%CI: 0.582 to 9.745), respectively. Univariate Cox analysis of CD147 expression and clinical characteristics of HCC and multivariate Cox analysis of CD147 patterns and pathological tumor-node-metastasis stage showed significant differences (univariate Cox, P = 0.00013, HR: 1.424, 95%CI: 1.884 to 1.707 and P = 0.00066, HR: 1.376, 95%CI: 1.145 to 1.654, respectively; multivariate Cox, P = 0.00578, HR: 1.507, 95%CI: 1.126 to 2.018 and P = 0.00336, HR: 1.443, 95%CI: 1.129 to 1.844, respectively). Nomograms were plotted to establish the probability points and predict prognosis. The total points ranged from 0 to 180, and the C-index value was 0.673 (95%CI: 0.600 to 1.000, P < 0.01). CONCLUSION: Overexpression of CD147 was correlated with poor prognosis in HCC. The CD147 expression profile combined with clinical characteristics can reliably predict the prognosis of HCC. CD147 can serve as a biomarker to predict the prognosis of HCC.

[Quality evaluation of Huocao based on UPLC fingerprint and multi-component content determination].

Huocao(a traditional Chinese herbal medicine) moxibustion is a characteristic technology in Yi medicine suitable for cold-dampness diseases. Huocao, as the moxibustion material, is confusedly used in clinical practice and little is known about its quality control. In this study, UPLC method was used to establish the chemical fingerprint of non-volatile components in Huocao, and the contents of eight phenolic acids such as chlorogenic acid were determined. Multivariate statistical analysis was performed to obtain the indicator components of Huocao for quality evaluation, and thus a comprehensive evaluation system for the quality of Huocao was built. The UPLC fingerprints of 49 batches of Huocao were established, and there were 20 common peaks, of which eight phenolic acids including neochlorogenic acid and chlorogenic acid were identified. Except for three batches of Huocao, the similarity of the other 46 batches was higher than 0.89, suggesting that the established fingerprint method could be used for quality control of the medicinal herb. The correlation coefficient between entropy weight score of the eight phenolic acids and comprehensive fingerprint score in Huocao was 0.875(P<0.01), which indicated that the eight phenolic acids could be used as indicator components for the quality evaluation of Huocao. Furthermore, in multivariate statistical analysis on the common peaks of fingerprint and the contents of the eight phenolic acids, chlorogenic acid, isochlorogenic acid A and isochlorogenic acid C were screened to be the indicator components. The results revealed that the proposed method achieved a simple and accurate quality control of Huocao based on UPLC fingerprint and multi-component content determination, which provided useful data for establishing the quality standard of Huocao.

[Main components from cultivated and wild Nardostachyos Radix et Rhizoma by LC-MS and GC-MS].

In this study, ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and gas chromatography-mass spectrometry(GC-MS) were combined with non-targeted metabonomic analysis based on multivariate statistics analysis, and the content of five indicative components in nardosinone was determined and compared by UPLC. The main chemical components of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma were comprehensively analyzed. The results of multivariate statistical analysis based on liquid chromatography-mass spectrometry(LC-MS) and GC-MS were consistent. G1 and G2 of the imitative wild cultivation group and G8-G19 of the wild group were clustered into category 1, while G7 of the wild group and G3-G6 of the imitative wild cultivation group were clustered into category 2. After removing the outlier data of G1, G2, and G7, G3-G6 of the imitative wild cultivation group were clustered into one category, and G8-G19 of the wild group were clustered into the other category. Twenty-six chemical components were identified according to the positive and negative ion modes detected by LC-MS. The content of five indicative components(VIP>1.5) was determined using UPLC, revealing that chlorogenic acid, isochlorogenic acid A, isochlorogenic acid C, linarin, nardosinone, and total content in the imitative wild cultivation group were 1.85, 1.52, 1.26, 0.90, 2.93, and 2.56 times those in the wild group, respectively. OPLS-DA based on GC-MS obtained 10 diffe-rential peaks. Among them, the relative content of α-humulene and aristolene in the imitative wild cultivation group were extremely significantly(P<0.01) and significantly(P<0.05) higher than that in the wild group, while the relative content of 7 components such as 5,6-epoxy-3-hydroxy-7-megastigmen-9-one, γ-eudesmol, and juniper camphor and 12-isopropyl-1,5,9-trimethyl-4,8,13-cyclotetrade-catriene-1,3-diol was extremely significantly(P<0.01) and significantly(P<0.05) lower than that in the wild group, respectively. Therefore, the main chemical components of the imitative wild cultivation group and wild group were basically the same. However, the content of non-volatile components in the imitative wild cultivation group was higher than that in the wild group, and the content of some volatile components was opposite. This study provides scientific data for the comprehensive evaluation of the quality of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma.

Synthetic organic antibiotics residues as emerging contaminants waste-to-resources processing for a circular economy in China: Challenges and perspective.

Synthetic antibiotics have been known for years to combat bacterial antibiotics. But their overuse and resistance have become a concern recently. The antibiotics reach the environment, including soil from the manufacturing process and undigested excretion by cattle and humans. It leads to overburden and contamination of the environment. These organic antibiotics remain in the environment for a very long period. During this period, antibiotics come in contact with various flora and fauna. The ill manufacturing practices and inadequate wastewater treatment cause a severe problem to the water bodies. After pretreatment from pharmaceutical industries, the effluents are released to the water bodies such as rivers. Even after pretreatment, effluents contain a significant number of antibiotic residues, which affect the living organisms living in the water bodies. Ultimately, river contaminated water reaches the ocean, spreading the contamination to a vast environment. This review paper discusses the impact of synthetic organic contamination on the environment and its hazardous effect on health. In addition, it analyzes and suggests the biotechnological strategies to tackle organic antibiotic residue proliferation. Moreover, the degradation of organic antibiotic residues by biocatalyst and biochar is analyzed. The circular economy approach for waste-to-resource technology for organic antibiotic residue in China is analyzed for a sustainable solution. Overall, the significant challenges related to synthetic antibiotic residues and future aspects are analyzed in this review paper.

Carbonylative Polymerization of Epoxides Mediated by Tri-metallic Complexes: A Dual Catalysis Strategy for Synthesis of Biodegradable Polyhydroxyalkanoates.

Polyhydroxyalkanoates (PHAs) are a unique class of commercially manufactured biodegradable polyesters with properties suitable for partially substituting petroleum-based plastics. However, high costs and low volumes of production have restricted their application as commodity materials. In this study, tri-metallic complexes were developed for carbonylative polymerization via a dual catalysis strategy, and 17 products of novel PHAs with up to 38.2 kg mol-1 Mn values were discovered. The polymerization proceeds in a sequential fashion, which entails the carbonylative ring expansion of epoxide to ß-lactone and its subsequent ring-opening polymerization that occurs selectively at the O-alkyl bond via carboxylate species. The wide availability and structural diversity of epoxide monomers provide PHAs with various structures, excellent functionalities, and tunable properties. This study represents a rare example of the preparation of PHAs using epoxides and carbon monoxide as raw materials.

Chlorogenic acid effectively treats cancers through induction of cancer cell differentiation.

RATIONALE: Inducing cancer differentiation is a promising approach to treat cancer. Here, we identified chlorogenic acid (CA), a potential differentiation inducer, for cancer therapy, and elucidated the molecular mechanisms underlying its differentiation-inducing effects on cancer cells. METHODS: Cancer cell differentiation was investigated by measuring malignant behavior, including growth rate, invasion/migration, morphological change, maturation, and ATP production. Gene expression was analyzed by microarray analysis, qRT-PCR, and protein measurement, and molecular biology techniques were employed for mechanistic studies. LC/MS analysis was the method of choice for chemical detection. Finally, the anticancer effect of CA was evaluated both in vitro and in vivo. Results: Cancer cells treated with CA showed reduced proliferation rate, migration/invasion ability, and mitochondrial ATP production. Treating cancer cells with CA resulted in elevated SUMO1 expression through acting on its 3'UTR and stabilizing the mRNA. The increased SUMO1 caused c-Myc sumoylation, miR-17 family downregulation, and p21 upregulation leading to G0/G1 arrest and maturation phenotype. CA altered the expression of differentiation-related genes in cancer cells but not in normal cells. It inhibited hepatoma and lung cancer growth in tumor-bearing mice and prevented new tumor development in naïve mice. In glioma cells, CA increased expression of specific differentiation biomarkers Tuj1 and GFAP inducing differentiation and reducing sphere formation. The therapeutic efficacy of CA in glioma cells was comparable to that of temozolomide. CA was detectable both in the blood and brain when administered intraperitoneally in animals. Most importantly, CA was safe even at very high doses. CONCLUSION: CA might be a safe and effective differentiation-inducer for cancer therapy. "Educating" cancer cells to differentiate, rather than killing them, could be a novel therapeutic strategy for cancer.

Riparian leaf litter decomposition on pond bottom after a retention on floating vegetation.

Allochthonous (e.g., riparian) plant litter is among the organic matter resources that are important for wetland ecosystems. A compact canopy of free-floating vegetation on the water surface may allow for riparian litter to remain on it for a period of time before sinking to the bottom. Thus, we hypothesized that canopy of free-floating vegetation may slow decomposition processes in wetlands. To test the hypothesis that the retention of riparian leaf litter on the free-floating vegetation in wetlands affects their subsequent decomposition on the bottom of wetlands, a 50-day in situ decomposition experiment was performed in a wetland pond in subtropical China, in which litter bags of single species with fine (0.5 mm) or coarse (2.0 mm) mesh sizes were placed on free-floating vegetation (dominated by Eichhornia crassipes, Lemna minor, and Salvinia molesta) for 25 days and then moved to the pond bottom for another 25 days or remained on the pond bottom for 50 days. The leaf litter was collected from three riparian species, that is, Cinnamomum camphora, Diospyros kaki, and Phyllostachys propinqua. The retention of riparian leaf litter on free-floating vegetation had significant negative effect on the carbon loss, marginal negative effects on the mass loss, and no effect on the nitrogen loss from leaf litter, partially supporting the hypothesis. Similarly, the mass and carbon losses from leaf litter decomposing on the pond bottom for the first 25 days of the experiment were greater than those from the litter decomposing on free-floating vegetation. Our results highlight that in wetlands, free-floating vegetation could play a vital role in litter decomposition, which is linked to the regulation of nutrient cycling in ecosystems.

Iridoids from Valeriana jatamansi induce autophagy-associated cell death via the PDK1/Akt/mTOR pathway in HCT116 human colorectal carcinoma cells.

Chlorovaltrates U-W (1-3), three previously undescribed iridoids, together with four known analogues were isolated from the roots of Valeriana jatamansi. Their structures were elucidated by means of spectroscopic analyses (HRESIMS, NMR). The cytotoxicity of all isolates was evaluated. Compounds 5-7 exhibited selective cytotoxicity against HCT116 cells, with IC50 values of 9.3, 1.7 and 2.2 µM, respectively. The preliminary mechanistic study revealed that, the cytotoxicity effect of 6 was attributed to Akt/mTOR activation blockade via inhibition of PDK1 phosphorylation. Meanwhile, compound 6 could induce autophagosome formation in HCT116 cells via suppressing its downstream Akt/mTOR. These findings show that compound 6 could be of great importance to the development of anti-colon cancer agents.

Pond-bottom decomposition of leaf litters canopied by free-floating vegetation.

In wetland ecosystems, vegetation can float freely on water surface, forming dense canopy which may play important ecological roles. This is especially true in many urban wetlands in which fluidity is low and nutrient level is high. So far, effects of free-floating vegetation on abiotic and biotic factors of wetlands have been known, while little on wetland ecosystem functions such as litter decomposition. To examine whether the canopy of free-floating vegetation on water surface will influence litter decomposition in wetlands or not, we conducted a 50-day in situ decomposition experiment in a subtropical urban pond wetland, in which litter bags of nine combinations of three mesh sizes and three litter species were put on the bottoms of total 22 ponds which were half with and half without free-floating vegetation canopy on the water surface. The ponds with and without the canopy had different water physicochemical properties. Overall, the canopy, the species identity, and the mesh size significantly decelerated mass loss and carbon loss of leaf litters while slightly on nitrogen loss. Effects of the canopy on leaf litter decomposition also showed species- and mesh size-dependent. Our results suggest that free-floating vegetation on water surface can alter water environmental factors and consequently change ecosystem functioning in wetlands.

The role of Fusobacterium nucleatum in colorectal cancer: from carcinogenesis to clinical management.

Colorectal cancer (CRC) is a common malignant tumor that affects people worldwide. Metagenomic analyses have shown an enrichment of Fusobacterium nucleatum (F. nucleatum) in colorectal carcinoma tissue; many studies have indicated that F. nucleatum is closely related to the colorectal carcinogenesis. In this review, we provide the latest information to reveal the related molecular mechanisms. The known virulence factors of F. nucleatum promote adhesion to intestinal epithelial cells via FadA and Fap2. Besides, Fap2 also binds to immune cells causing immunosuppression. Furthermore, F. nucleatum recruits tumor-infiltrating immune cells, thus yielding a pro-inflammatory microenvironment, which promotes colorectal neoplasia progression. F. nucleatum was also found to potentiate CRC development through toll-like receptor 2 (TLR2)/toll-like receptor 4 (TLR4) signaling and microRNA (miRNA)-21 expression. In addition, F. nucleatum increases CRC recurrence along with chemoresistance by mediating a molecular network of miRNA-18a*, miRNA-4802, and autophagy components. Moreover, viable F. nucleatum was detected in mouse xenografts of human primary colorectal adenocarcinomas through successive passages. These findings indicated that an increased number of F. nucleatum in the tissues is a biomarker for the diagnosis and prognosis of CRC, and the underlying molecular mechanism can probably provide a potential intervention treatment strategy for patients with F. nucleatum-associated CRC.

[Grading standard of processed Curcumae Radix].

As one of the three pillars of Chinese medicine industry, traditional Chinese medicines prepared in ready-to-use forms are important raw materials for clinical medication and production of Chinese patent drugs. By considering the literature of Curcumae Radix, a multi-source Chinese herb and the situation of market investigation, the modern evaluation method based on traditional grading was introduced for comprehensive evaluation of the processed Curcumae Radix. The correlation between traditional grading method and modern evaluation index was explored to establish the grading standard of Curcumae Radix. According to the comprehensive evaluation, Curcumae Radix was divided into four grades: superior, first, second and third grades under the guidance of the theory of traditional Chinese medicine. This study provides a new idea for the grading of multi-source processed Chinese medicine, achieving high quality and good price, which is helpful to improve the clinical efficacy.

Intraspecific N and P stoichiometry of Phragmites australis: geographic patterns and variation among climatic regions.

Geographic patterns in leaf stoichiometry reflect plant adaptations to environments. Leaf stoichiometry variations along environmental gradients have been extensively studied among terrestrial plants, but little has been known about intraspecific leaf stoichiometry, especially for wetland plants. Here we analyzed the dataset of leaf N and P of a cosmopolitan wetland species, Phragmites australis, and environmental (geographic, climate and soil) variables from literature and field investigation in natural wetlands distributed in three climatic regions (subtropical, temperate and highland) across China. We found no clear geographic patterns in leaf nutrients of P. australis across China, except for leaf N:P ratio increasing with altitude. Leaf N and N:P decreased with mean annual temperature (MAT), and leaf N and P were closely related to soil pH, C:N ratio and available P. Redundancy analysis showed that climate and soil variables explained 62.1% of total variation in leaf N, P and N:P. Furthermore, leaf N in temperate region and leaf P in subtropical region increased with soil available P, while leaf N:P in subtropical region decreased with soil pH. These patterns in P. australis different from terrestrial plants might imply that changes in climate and soil properties can exert divergent effects on wetland and terrestrial ecosystems.

CO2-Mediated Formation of Chiral Carbamates from meso-Epoxides via Polycarbonate Intermediates.

Carbon dioxide has attracted broad interest as a renewable C1 feedstock for efficient transformation into value-added organic chemicals; nevertheless, far less attention was paid to its stereochemically controlled catalytic fixation/conversion processes. Here, we report a new strategy for the selective synthesis of chiral carbamates from carbon dioxide via polycarbonate intermediates, which are formed by the desymmetric copolymerization of meso-epoxides using enantiopure dinuclear Co(III) catalyst systems with 99% enantioselectivity. Subsequent degradation reaction of the resultant polycarbonates with various primary or secondary amine nucleophiles can afford optically active carbamates, with the complete configuration retention of the two chiral carbon centers. Our accomplishment reported here opens up a new route to prepare a wide range of CO2-based carbamate scaffolds with excellent yields and 99% enantiomeric excess.

[Expression of plateau adaptation gene of rat tissues after plain acute exposure to high altitude].

OBJECTIVE: To detect the expression of the plateau adaptablity gene(EPAS1, EGLN1 and PPARα) and proteins(HIF-2, PHD2 and PPARα) in rats blood, heart, liver, lung and kidney tissue after the rats exposed to high altitude. METHODS: The Wistar rats were randomly divided into plain group(Shanghai, 55 m), acute exposure to high altitude 3400 m group, acute exposure to high altitude 4300 m group. Blood and organs of rats were collected in 1, 3, 5 days after arrival. Real time PCR and ELISA were used to compare the expression of plateau adaptablity gene and related protein between plain group and high altitude exposure groups. RESULTS: The count of red blood cells, hemoglobin and HCT in high altitude 4300 m were higher than those in plain group. Compared with plain group, the expression of EPAS1 gene in blood, heart, liver and kidney tissue of rats at high altitude increased obviously(all P<0.05); the expression of EGLN1 in the heart, liver, brain and kidney increased, and PPARα gene in the heart, liver and kidney increased(all P<0.05). Compared with plain group, the expression of HIF-2 protein increased significantly at high altitudes in the liver, brain and kidney tissues. PHD2 and PPARα increased in the heart, liver and kidney. CONCLUSION: Plateau adaptive genes(EPAS1, EGLN1 and PPARα) and protein(HIF-2, PHD2 and PPARα) differed in different altitude and different organizations. They might be used as target markers of plateau hypoxia.

Novel evidence for within-species leaf economics spectrum at multiple spatial scales.

Leaf economics spectrum (LES), characterizing covariation among a suite of leaf traits relevant to carbon and nutrient economics, has been examined largely among species but hardly within species. In addition, very little attempt has been made to examine whether the existence of LES depends on spatial scales. To address these questions, we quantified the variation and covariation of four leaf economic traits (specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus contents) in a cosmopolitan wetland species (Phragmites australis) at three spatial (inter-regional, regional, and site) scales across most of the species range in China. The species expressed large intraspecific variation in the leaf economic traits at all of the three spatial scales. It also showed strong covariation among the four leaf economic traits across the species range. The coordination among leaf economic traits resulted in LES at all three scales and the environmental variables determining variation in leaf economic traits were different among the spatial scales. Our results provide novel evidence for within-species LES at multiple spatial scales, indicating that resource trade-off could also constrain intraspecific trait variation mainly driven by climatic and/or edaphic differences.

[Influence of Spectral Pre-Processing on PLS Quantitative Model of Detecting Cu in Navel Orange by LIBS].

Cu in navel orange was detected rapidly by laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) for quantitative analysis, then the effect on the detection accuracy of the model with different spectral data ptetreatment methods was explored. Spectral data for the 52 Gannan navel orange samples were pretreated by different data smoothing, mean centralized and standard normal variable transform. Then 319~338 nm wavelength section containing characteristic spectral lines of Cu was selected to build PLS models, the main evaluation indexes of models such as regression coefficient (r), root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were compared and analyzed. Three indicators of PLS model after 13 points smoothing and processing of the mean center were found reaching 0. 992 8, 3. 43 and 3. 4 respectively, the average relative error of prediction model is only 5. 55%, and in one word, the quality of calibration and prediction of this model are the best results. The results show that selecting the appropriate data pre-processing method, the prediction accuracy of PLS quantitative model of fruits and vegetables detected by LIBS can be improved effectively, providing a new method for fast and accurate detection of fruits and vegetables by LIBS.