Flavonoid Metabolic Profiles and Gene Mapping of Rice (Oryza sativa L.) Purple Gradient Grain Hulls.

Rice (Oryza sativa L.) grain hull color is an easily observable trait and regarded as a crucial morphological marker in rice breeding. Here, a purple gradient grain hull mutant (pg) was found from natural mutations of a straw-white grain hull rice variety IARI 6184B (Orzya sativa L. subsp. indica). The color of the mutant grain hulls changed from straw-white to pink, then purple, and finally brownish-yellow. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) identified 217 flavonoids, including 18 anthocyanins, among which cyanidin O-syringic acid had the highest concentration in pink (66.2 × 106) and purple (68.0 × 106) grain hulls. The relative contents of hesperetin O-malonyl-hexoside, apigenin derivatives, genistein derivatives, and kaempferol 3-O derivatives were consistently downregulated during pg grain hull development. Conversely, 12 anthocyanins were upregulated in colored hulls, and cyanidin 3-O-malonylhexoside was abundant only in pink and purple grain hulls. Moreover, the candidate gene was mapped into a 1.38 Mb region on chromosome 4 through bulked segregant analysis based on deep sequencing (BSA-seq) and gene mapping approaches. These results increased our understanding of anthocyanin biosynthesis in rice grains, helping rice breeders to select new rice varieties with desirable grain traits.

Metabolomic Profiling of Dongxiang Wild Rice Under Salinity Demonstrates the Significant Role of Amino Acids in Rice Salt Stress.

Dongxiang common wild rice is a precious rice germplasm resource for the study and improvement of salt tolerance in rice.The metabolism profile of Dongxiang wild rice (DXWR) under salinity was determined by high performance liquid chromatography-mass spectrometry (HPLC-MS) to find differential metabolites and screen potential biomarkers for salt-tolerant rice varieties. A global untargeted metabolism analysis showed 4,878 metabolites accumulated in seedlings of Dongxiang wild rice. Principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) results provided a clear metabolism discrimination between DXWR under control and DXWR under salinity. A total of 90 metabolites were significantly changed (49 upregulated and 41 downregulated) under salinity, of which the largest increase was in DL-2-Aminoadipic acid (27.08-fold) and the largest decrease was in L-Carnitine (0.014-fold). Amino acids and nuclear glycosides were mainly upregulated, while carbohydrates and organic acids were mainly downregulated in the salt-treated group. Among the top 10 upregulated metabolites, five kinds of differential metabolites were amino acids. According to the survival rates of the seedlings under salinity, we selected three backcross inbred lines of DXWR with survival rates above 80% as salt-tolerant progenies (pro-DS) and three backcross inbred lines with survival rates below 10% as non-salt-tolerant progenies (pro-NDS) for an amino acid change analysis. This analysis found that the change in L-Asparagine (2.59-fold) was the biggest between pro-DS and pro-NDS under salinity, revealing that the contents of L-Asparagine may be one of the indices we can use to evaluate the salt tolerance of rice varieties.

Pro-inflammatory cytokine interleukin-6-induced hepcidin, a key mediator of periodontitis-related anemia of inflammation.

OBJECTIVES: To investigate whether anemia of inflammation (AI) occurs in periodontitis patients and to further explore underlying pathogenesis of periodontitis-related AI by an experimental periodontitis model. BACKGROUND: Previous studies have reported periodontitis patients could show a tendency toward AI. However, the relationship between periodontitis and AI remains unclear, and the related pathological mechanisms have not been identified. MATERIALS AND METHODS: Periodontal clinical parameters, inflammatory markers, and anemia-related indicators were compared between 98 aggressive periodontitis (AgP) patients and 103 healthy subjects. An experimental periodontitis model was induced by ligature placement in mice. The changes in mice inflammatory markers, anemia indicators, hepcidin mRNA expression, and serum hepcidin concentrations were measured. Human and mouse liver cells were treated with interleukin-6 (IL-6) for analyzing the changes in hepcidin expression based on mRNA and protein levels. RESULTS: AgP patients exhibited higher white blood cell counts, IL-6, and C-reactive protein. Adjusted linear regression analyses showed correlations between AgP and decreased hemoglobin (HGB) and hematocrit (HCT). The ligature-induced periodontitis caused systemic inflammation and elevated IL-6 levels. Lower red blood cell counts, HGB, and HCT were detected, whereas the levels of hepcidin mRNA expression and serum hepcidin concentrations increased. The treatment of hepatocytes with IL-6 induced both hepcidin mRNA expression and hepcidin secretion. CONCLUSIONS: Systemic inflammation induced by periodontitis leads to an increased risk for AI. IL-6-induced hepcidin could play a central mediator role and act as a key pathologic mechanism. Our results demonstrate periodontitis may be considered as an additional inflammatory disease contributing to the development of AI.

Variability of Volatile Compounds in the Medicinal Plant Dendrobium officinale from Different Regions.

Dendrobium officinale Kimura et Migo, a rare and traditional medicinal plant, contains many nutrients such as polysaccharides, alkaloids, amino acids and so on. Different growth environment and intraspecific hybridization of different germplasm resources lead to large differences in the yield, quality and medicinal value of D. officinale. Here, the volatile compounds of D. officinale from four producing regions (Zhejiang, Fujian, Yunnan and Jiangxi) were analyzed to provide a certain reference value for the selection of a specific medicinal component in D. officinale breeding. Fresh stems of D. officinale germplasm resources were collected, and the chemical constituents were determined by gas chromatography-mass spectrometry. A total of 101 volatile compounds were identified, of which esters and alcohols accounted for 23 and 22. Hexacosane is the highest relative content of all volatile components. The highest content of hexacosane was observed in YA1 from Yunnan was 34.41%, and the lowest (23.41%) in JA1 from Jiangxi. Moreover, 5-10 unique substances were determined in different regions. A total of 17 medicinal components were detected, and three unique medicinal components were detected only in YA1, revealing that YA1 can provide raw materials for the application of specific medicinal substances extraction. A total of four toxic components were detected, but no toxic components were detected in JA1 from Jiangxi, suggested that the germplasm resources from Jiangxi could be exploited efficiently for breeding superior D. officinale specimens. The results provide a theoretical basis for the collection, protection and utilization of D. officinale germplasm resources in different regions.

Platelets as inflammatory mediators in a murine model of periodontitis.

AIM: To investigate the role of platelets during the development of ligature-induced experimental periodontitis in mice. MATERIALS AND METHODS: Experimental periodontitis was induced by placement of sterilized 5-0 cotton ligatures around the maxillary and mandibular second molars of C57BL/6 wild-type mice. Flow cytometry was used to analyse platelet activation and platelet-leucocyte aggregate formation, and histologic analysis was used to evaluate inflammation and localization of platelets and leucocytes in periodontal tissues during the development of experimental periodontitis and in experimental periodontitis with and without antiplatelet drug treatment. RESULTS: Experimental periodontitis induced platelet activation and platelet-leucocyte interaction. Platelets and leucocytes gradually infiltrated in inflammatory gingival tissues during the development of experimental periodontitis. The inhibition of platelet activation via drug therapy led to significant inhibition of leucocyte migration and marked reduction in periodontal inflammation. CONCLUSION: This study revealed that platelets are critical for inflammation and tissue injury in periodontitis and serve as mediators of inflammation in periodontal tissue.

Ferritin expression in the periodontal tissues of primates.

Ferritin, an iron-binding protein, is composed of two subunits, a heavy chain and a light chain. It regulates many biological functions, such as proliferation, angiogenesis, and immunosuppression. The objective of this study was to determine the expression and distribution of ferritin in the periodontal tissuesof primates.First, we assessed the expression of ferritin in primary cultured cells isolated from human periodontal tissues using the polymerase chain reaction and immunofluorescent staining. Second, we investigated the expression and distribution of ferritin in the periodontal tissues of Macaca fascicularis, human gingival tissues, and human gingival carcinoma tissues using immunohistochemistry.Both protein and mRNA of ferritin were constitutively present in human primary cultured cells, including those from the dental apical papilla, periodontal ligament, dental pulp, and gingival epithelium, as well as gingival fibroblasts. In M. fascicularistissues, the immunohistochemical staining was particularly strong in blood vessel and mineralizing areas of the dental pulp and periodontal ligament. Ferritin heavy chain exhibited specific immunopositivity in in the stratum basale of the epithelium in human gingival tissue and strong immunostaining was found in peripheral regions of gingival carcinoma sites. Ferritin is constitutivelypresent andwidelydistributed in the periodontal tissues of primates. Ferritin may play roles in epithelial proliferation, vascular angiogenesis, and mineralization in these tissues.

Up-regulated ferritin in periodontitis promotes inflammatory cytokine expression in human periodontal ligament cells through transferrin receptor via ERK/P38 MAPK pathways.

OBJECTIVE: Ferritin, an iron-binding protein, is ubiquitous and highly conserved; it plays a crucial role in inflammation, which is the main symptom of periodontitis. Full-length cDNA library analyses have demonstrated abundant expression of ferritin in human periodontal ligament. The aims of the present study were to explore how ferritin is regulated by local inflammation, and to investigate its functions and mechanisms of action in the process of periodontitis. METHODS: Human gingival tissues were collected from periodontitis patients and healthy individuals. Experimental periodontitis was induced by ligature of second molars in mice. The expression of ferritin light polypeptide (FTL) and ferritin heavy polypeptide (FTH) were assessed by immunohistochemistry. Meanwhile, after stimulating human periodontal ligament cells (HPDLCs) with P. gingivalis-lipopolysaccharide (LPS), interleukin (IL)-6, and tumor necrosis factor-α (TNF-α), the expression of FTH and FTL were measured. Then, IL-6 and IL-8 were measured after incubation with different concentrations of apoferritin (iron-free ferritin) and several intracellular signaling pathway inhibitors, or after knockdown of the transferrin receptor. RESULTS: Both FTH and FTL were substantially higher in inflamed periodontal tissues than in healthy tissues. The location of the elevated expression correlated well with the extent of inflammatory infiltration. Moreover, expression of FTH and FTL were enhanced after stimulation with P. gingivalis-LPS, IL-6, TNF-α. Apoferritin induced the production of IL-6 and IL-8 in a dose-dependent manner partly through binding to the transferrin receptor and activating ERK/P38 signaling pathways in HPDLCs. CONCLUSIONS: Ferritin is up-regulated by inflammation and exhibits cytokine-like activity in HPDLCs inducing a signaling cascade that promotes expression of pro-inflammatory cytokines associated with periodontitis.

Aptamer and 5-fluorouracil dual-loading Ag2S quantum dots used as a sensitive label-free probe for near-infrared photoluminescence turn-on detection of CA125 antigen.

In this article, Ag2S quantum dots (QDs) were prepared by a facile aqueous synthesis method, using thiourea as a new sulfur precursor. Based on electrostatic interactions, 5-fluorouracil (5-Fu) was combined with the aptamer of CA125 antigen to fabricate aptamer/5-Fu complex. The surface of as-prepared Ag2S QDs was modified with polyethylenimine, followed by combination with the aptamer/5-Fu complex to form Ag2S QDs/aptamer/5-Fu hybrids. During the combination of Ag2S QDs with aptamer/5-Fu complex, near-infrared (NIR) photoluminescence (PL) of QDs (peaked at 850nm) was markedly reduced under excitation at 625nm, attributed to photo-induced electron transfer from QDs to 5-Fu. However, the addition of CA125 induced obvious NIR PL recovery, which was ascribed to the strong binding affinity of CA125 with its aptamer, and the separation of aptamer/5-Fu complex from the surface of QDs. Hence, the Ag2S QDs/aptamer/5-Fu hybrids were developed as a novel NIR PL turn-on probe of CA125. In the concentration range of [CA125] from 0.1 to 106ngmL-1, there were a good linear relationship between NIR PL intensities of Ag2S QDs and Log[CA125], and a low limit of detection of 0.07ngmL-1. Experimental results revealed the highly selective and sensitive NIR PL responses of this probe to CA125, over other potential interferences. In real human body fluids, this probe also exhibited superior analytical performance, together with high detection recoveries.

Synthesis of Chiral Piperazines via Hydrogenation of Pyrazines Activated by Alkyl Halides.

A facile method has been developed for the synthesis of chiral piperazines through Ir-catalyzed hydrogenation of pyrazines activated by alkyl halides, giving a wide range of chiral piperazines including 3-substituted as well as 2,3- and 3,5-disubstituted ones with up to 96% ee. The high enantioselectivity, easy scalability, and concise drug synthesis demonstrate the practical utility.

Enantioselective palladium-catalyzed C-H functionalization of indoles using an axially chiral 2,2'-bipyridine ligand.

A palladium-catalyzed enantioselective CH functionalization of indoles was achieved with an axially chiral 2,2'-bipyridine ligand, thus providing the desired indol-3-acetate derivatives with up to 98 % ee. Moreover, the reaction protocol was also effective for asymmetric OH insertion reaction of phenols using α-aryl-α-diazoacetates. This represents the first successful application of bipyridine ligands with axial chirality in palladium-catalyzed carbene migratory insertion reactions.

Iridium-catalyzed selective hydrogenation of 3-hydroxypyridinium salts: a facile synthesis of piperidin-3-ones.

The selective hydrogenation of 3-hydroxypyridinium salts has been achieved using a homogeneous iridium catalyst, providing a direct access to 2- and 4-substituted piperidin-3-one derivatives with high yields, which are important organic synthetic intermediates and the prevalent structural motifs in pharmaceutical agents. Mild reaction conditions, high chemoselectivity, and easy scalability make this reaction highly practical for the synthesis of piperidin-3-ones.

Formal palladium-catalyzed asymmetric hydrogenolysis of racemic N-sulfonyloxaziridines.

Highly enantioselective palladium-catalyzed formal hydrogenolysis of racemic N-sulfonyloxaziridines has been realized, providing a novel access to sultams with up to 99% ee. Preliminary mechanistic insights revealed that the reaction proceeded through a N-O bond cleavage, dehydration, and the sequential asymmetric hydrogenation.

Asymmetric hydrogenation via capture of active intermediates generated from aza-Pinacol rearrangement.

An efficient palladium-catalyzed asymmetric hydrogenation via capture of an active intermediate generated in situ from acid-catalyzed aza-Pinacol rearrangement has been successfully developed, providing efficient access to chiral exocyclic amines with up to 98% ee. Three-, four-, and five-membered cyclic N-sulfonyl amino alcohols are viable substrates. This study opens a new window to the application of asymmetric hydrogenation.

Palladium-catalyzed asymmetric hydrogenation of 3-phthalimido substituted quinolines.

Homogeneous Pd-catalyzed asymmetric hydrogenation of 3-phthalimido substituted quinolines was successfully developed, providing facile access to chiral substituted tetrahydroquinolines bearing two contiguous stereogenic centers with up to 90% ee.

Iridium-catalyzed asymmetric hydrogenation of pyrrolo[1,2-a]pyrazinium salts.

Highly enantioselective iridium-catalyzed hydrogenation of pyrrolo[1,2-a]pyrazinium salts has been achieved, providing a direct access to chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives with up to 95% ee. The key feature of the reaction is the addition of cesium carbonate, which increases the conversion and prohibits the racemization pathway of products.

An improved method for ratiometric fluorescence detection of pH and Cd2+ using fluorescein isothiocyanate-quantum dots conjugates.

In this study, thioglycolic acid capped-CdTe quantum dots (QDs) were modified by polyethylenimine (PEI), and then combined with fluorescein isothiocyanate (FITC) to fabricate FITC-CdTe conjugates. The self-assembly of FITC, CdTe and PEI was ascribed to electrostatic interactions in aqueous solution. The resulting conjugates were developed toward two routes. In route one, ratiometric photoluminescence (PL) intensity of conjugates (IFITC/IQDs) was almost linear toward pH from 5.3 to 8.7, and a ratiometric PL sensor of pH was favorable obtained. In route two, firstly added S(2-) induced remarkable quenching of QDs PL peak (at the "OFF" state), which was restored due to following addition of Cd(2+) (at the "ON" state). In the conjugates, successive introduction of S(2-) and Cd(2+) hardly influenced on FITC PL peaks. According to this PL "OFF-ON" mode, a ratiometric PL method for the detection of Cd(2+) was achieved. Experimental results confirmed that the IFITC/IQDs exhibited near linear proportion toward Cd(2+) concentration in the range from 0.1 to 15µM, and the limit of detection was 12nM. Interferential experiments adequately testified that the proposed sensors of pH and Cd(2+) were practicable in real samples and complex systems. In comparison with conventional analytical techniques, the ratiometric PL method was simple, rapid, economic and highly selective.

Revised rates for the stellar triple-alpha process from measurement of 12C nuclear resonances.

In the centres of stars where the temperature is high enough, three alpha-particles (helium nuclei) are able to combine to form 12C because of a resonant reaction leading to a nuclear excited state. (Stars with masses greater than approximately 0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe, and for determining the size of the iron core of a star just before it goes supernova, it has hitherto been insufficiently determined. Here we report a measurement of the inverse process, where a 12C nucleus decays to three alpha-particles. We find a dominant resonance at an energy of approximately 11 MeV, but do not confirm the presence of a resonance at 9.1 MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-alpha rate for temperatures from 10(7) K to 10(10) K and find significant deviations from the standard rates. Our rate below approximately 5 x 10(7) K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed. At temperatures above 10(9) K, our rate is much less, which modifies predicted nucleosynthesis in supernovae.