RESUMEN
Cyclization of propargylamines with CO2 to obtain 2-oxazolidone heterocyclic compounds is an essential reaction in industry but it is usually catalyzed by noble-metal catalysts with organic bases as co-catalysts under harsh conditions. We have synthesized a unique CuI /CuII mixed valence copper-based framework {[(CuI 6 I5 )Cu3 II L6 (DMA)3 ](NO3 )â 9DMA}n (1) with good solvent and thermal stability, as well as a high density of uncoordinated amino groups evenly distributed in the large nanoscopic channels. Catalytic experiments show that 1 can effectively catalyze the reaction of propargylamines with CO2 , and the yield can reach 99 %. The turnover frequency (TOF) reaches a record value of 230â h-1 , which is much higher than that of reported noble-metal catalysts. Importantly, this is the first report of heterogeneously catalyzed green conversion of propargylamines with CO2 without solvents and co-catalysts under low temperature and atmospheric pressure. A mechanistic study reveals that a triply synergistic catalytic effect between CuI /CuII and uncoordinated amino groups promotes highly efficient and green conversion of CO2 . Furthermore, 1 directly catalyzes this reaction with high efficiency when using simulated flue gas as a CO2 source.
RESUMEN
Ulva spp. dominates green tides around the world, which are occurring at an accelerated rate. The competitive nitrogen assimilation efficiency in Ulva is suggested to result in ecological success against other seaweeds. However, molecular characterization of genes involved in nitrogen assimilation has not been conducted. Here, we describe the identification of the nitrate reductase (NR) gene from a green seaweed Ulva prolifera, an alga which is responsible for the world's largest green tide in the Yellow Sea. Using rapid amplification of cDNA ends and genome walking, the NR gene from U. prolifera (UpNR) was cloned, which consisted of six introns and seven exons encoding 863 amino acids. According to sequence alignment, the NR in U. prolifera was shown to possess all five essential domains and 21 key invariant residues in plant NRs. The GC content of third codon position of UpNR (82.75%) was as high as those of green microalgae, and the intron number supported a potential loss issue from green microalga to land plant. Real-time quantitative PCR results showed that UpNR transcript level was induced by nitrate and repressed by ammonium, which could not be removed by addition of extra nitrate, indicating that U. prolifera preferred ammonium to nitrate. Urea would not repress NR transcription by itself, while it weakened the induction effect of nitrate, implying it possibly inhibited nitrate uptake rather than nitrate reduction. These results suggest the use of UpNR as a gene-sensor to probe the N assimilation process in green tides caused by Ulva.
Asunto(s)
Proteínas Algáceas/genética , Nitrato-Reductasa/genética , Ulva/genética , Proteínas Algáceas/química , Proteínas Algáceas/metabolismo , Secuencia de Aminoácidos , China , Nitrato-Reductasa/química , Nitrato-Reductasa/metabolismo , Filogenia , Algas Marinas/genética , Algas Marinas/metabolismo , Alineación de Secuencia , Ulva/metabolismoRESUMEN
BACKGROUND: Increased sympathetic activity, commonly reported in mitral valve prolapse, indicates that the sympathetic nervous system might play an important role in regulating mitral interstitial cells. Hence, the aim of this study is to determine the level and pattern of adrenergic receptors expressed in human mitral valve leaflets and to investigate the effect of norepinephrine on physiologic behaviors of mitral interstitial cells. METHODS AND RESULTS: Immunohistochemistry displayed significantly increased expressions of ß1, ß2, and α1 adrenergic receptors in mitral valve prolapse. Norepinephrine was found to activate the phenotype of interstitial cells with increased α-SMA expression (2.26 fold). In synthesis, norepinephrine downregulated levels of mRNA for type I to type III collagen in ratio, but increased the elastin gene transcription and glycosaminoglycan levels in valve interstitial cells greatly. In view of the extracellular matrix remodel, sympathetic effects presented catabolic metabolism displaying significantly increased expressions of total, secretory and active MMP-2 protein (matrix metalloproteinase-2), as well as MMP-9 protein. Diminished MMP inhibitor expression, TIMP2, also could reflect this effect in the norepinephrine medium. CONCLUSIONS: A novel role for the sympathetic effect in influencing physiologic behaviors in mitral interstitial cells was identified. It is indicated that sympathetic activity could promote myxomatous degeneration in mitral valve prolapse, propagating the disease severity, which might identify potential therapeutic targets.
Asunto(s)
Regulación de la Expresión Génica , Insuficiencia de la Válvula Mitral/metabolismo , Prolapso de la Válvula Mitral/metabolismo , Proteínas Musculares/biosíntesis , Sistema Nervioso Simpático/metabolismo , Femenino , Humanos , Masculino , Insuficiencia de la Válvula Mitral/patología , Insuficiencia de la Válvula Mitral/cirugía , Prolapso de la Válvula Mitral/patología , Prolapso de la Válvula Mitral/cirugía , Sistema Nervioso Simpático/patologíaRESUMEN
To provide theoretical support the full use of water and fertilizer resources for wheat, we explored the effects of irrigation on wheat yield, plant and soil nutrient distribution during flowering period and its relationship with root characteristics. We set up two treatments by using the 2 m deep soil column cultivation method with irrigation during flowering (T1) and no irrigation during flowering (T2), with the drought-resistant and high-yield cultivar Luomai 28 (LM28) and the high photosynthetic efficiency cultivar Bainong 207 (BN207) as materials. We measured contents of nitrogen, phosphorus and potassium in plants and soils, as well as the characteristics of soil roots. The results showed that ammonium, available phosphorus, and available potassium were mainly distributed in 0-80 cm soil layer, and that nitrate was mainly distributed in soil layer below 80 cm during wheat harvest. Irrigation at anthesis stage promoted wheat to absorb ammonium, available phosphorus and available potassium from the upper layer of soil and nitrate nitrogen from the lower layer but did not aggravate the deep leaching of nitrate. The root of wheat mainly concentrated in 0-60 cm soil layer and decreased with increasing soil depth. Dry matter accumulation, total nitrogen and total phosphorus were mainly distributed in wheat grains at maturity, while total potassium was mainly distributed in stems. Irrigation at anthesis stage significantly increased the 100-grain weight of wheat, and consequently the yield. Root morphology was negatively correlated with soil nitrate in 0-40 cm soil layer, positively correlated with soil ammonium in 80-100 cm soil layer and soil available phosphorus in 0-100 cm soil layer. Irrigation at anthesis stage promoted the full absorption of soil nutrients by roots at late filling stage, delayed the senescence of flag leaves after flowering, prolonged the functional period of transporting nutrients from vegetative organs to reproductive organs, leading nutrients in vegetative organs more fully transported to grains, increasing grain weight and yield.
Asunto(s)
Riego Agrícola , Suelo , Riego Agrícola/métodos , Triticum , Nitratos/análisis , Biomasa , Nitrógeno/análisis , Agua , Grano Comestible/químicaRESUMEN
BACKGROUND: The concordance between mutations detected from plasma and tissue is critical for treatment choices of patients with advanced lung adenocarcinoma. METHODS: We prospectively analyzed the association of the serum tumor markers with the concordance between blood and tissue genomic profiles from 185 patients with advanced lung adenocarcinoma. The concordance was defined according to 3 criteria. Class 1 included all targetable driver mutations in 8 genes; class 2 included class 1 mutations plus mutations in KRAS, STK11, and TP53; class 3 included class 2 mutations plus tumor mutation burden (TMB) status. RESULTS: Collectively, 150 out of 185 patients had mutations in both tissue and plasma samples, while one patient was mutation-negative for both, resulting a concordance of 81.6%. The concordance rate for class 1 mutations was 80%, and 65% and 69% for class 2 and class 3, respectively. Carbohydrate antigen 19-9 (CA19-9) or cytokeratin 19 (CYFRA21-1) levels higher than the normal upper limit predicted the concordance of tissue and blood results in class 1 (P=0.005, P=0.011), class 2 (P=0.011, P<0.001), and class 3 (P=0.001, P=0.014). In class 1, the cutoff values of CA19-9 were 30, 36, and 284 U/mL to reach the concordance thresholds of 90%, 95%, and 100%, respectively (P=0.032, P=0.003, P=0.043). For CYFRA21-1, the cutoff values were 6, 18, and 52 µg/L (P=0.005, P=0.051, P=0.354). In class 2, the cutoff values for CYFRA21-1 were 18, 22, and 52 µg/L (P=0.001, P=0.001, P=0.052). In class 3, the cutoff values for CA19-9 were 36, 39, and 85 U/mL (P=0.003, P=0.001, P=0.008). For CYFRA21-1, the cutoff values were 22, 52, and 52 µg/L (P=0.900, P>0.99, P>0.99). When the sum score for 4 serum tumor markers was greater than 35, both class 1, class 2, and class 3 reached a predictive threshold of 90%. CONCLUSIONS: Serum tumor markers can be used as easy and practical clinical predictors of concordance in mutation profiles between blood and tissue samples from patients with advanced lung adenocarcinoma.