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1.
Xin Qiao Zhong-Ying Ma Jia Shao Wei-Guo Bao Jing-Yuan Xu Zhao-Yan Qiang Jian-Shi Lou 《Biometals》2014,27(1):155-172
Exploring novel chemotherapeutic agents is a great challenge in cancer medicine. To that end, 2-substituted benzimidazole copper(II) complex, [Cu(BMA)Cl2]·(CH3OH) (1) [BMA = N,N′-bis(benzimidazol-2-yl-methyl)amine], was synthesized and its cytotoxicity was characterized. The interaction between complex 1 and calf thymus DNA was detected by spectroscopy methods. The binding constant (K b = 1.24 × 104 M?1) and the apparent binding constant (K app = 6.67 × 106 M?1) of 1 indicated its moderate DNA affinity. Complex 1 induced single strand breaks of pUC19 plasmid DNA in the presence of H2O2 through an oxidative pathway. Cytotoxicity studies proved that complex 1 could inhibit the proliferation of human cervical carcinoma cell line HeLa in both time- and dose-dependent manners. The results of nuclei staining by Hoechst 33342 and alkaline single-cell gel electrophoresis proved that complex 1 caused cellular DNA damage in HeLa cells. Furthermore, treatment of HeLa cells with 1 resulted in S-phase arrest, loss of mitochondrial potential, and up-regulation of caspase-3 and -9 in HeLa cells, suggesting that complex 1 was capable of inducing apoptosis in cancer cells through the intrinsic mitochondrial pathway. 相似文献
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Dörte Randewig Domenica Hamisch Monika Eiblmeier Christian Boedecker Jürgen Kreuzwieser Ralf R. Mendel Robert Hänsch Cornelia Herschbach Heinz Rennenberg 《Trees - Structure and Function》2014,28(2):399-411
Key Message
The critical level for SO 2 susceptibility of Populus × canescens is approximately 1.2 μL L ?1 SO 2 . Both sulfite oxidation and sulfite reduction and assimilation contribute to SO 2 detoxification.Abstract
In the present study, uptake, susceptibility and metabolism of SO2 were analyzed in the deciduous tree species poplar (Populus × canescens). A particular focus was on the significance of sulfite oxidase (SO) for sulfite detoxification, as SO has been characterized as a safety valve for SO2 detoxification in herbaceous plants. For this purpose, poplar plants were exposed to different levels of SO2 (0.65, 0.8, 1.0, 1.2 μL L?1) and were characterized by visible injuries and at the physiological level. Gas exchange parameters (stomatal conductance for water vapor, CO2 assimilation, SO2 uptake) of the shoots were compared with metabolite levels (sulfate, thiols) and enzyme activities [SO, adenosine 5′-phosphosulfate reductase (APR)] in expanding leaves (80–90 % expanded). The critical dosage of SO2 that confers injury to the leaves was 1.2 μL L?1 SO2. The observed increase in sulfur containing compounds (sulfate and thiols) in the expanding leaves strongly correlated with total SO2 uptake of the plant shoot, whereas SO2 uptake rate was strongly correlated with stomatal conductance for water vapor. Furthermore, exposure to high concentration of SO2 revealed channeling of sulfite through assimilatory sulfate reduction that contributes in addition to SO-mediated sulfite oxidation to sulfite detoxification in expanding leaves of this woody plant species. 相似文献3.
Giuseppe Gambino Sara De Pinto Lorenzo Tei Claudio Cassino Francesca Arena Eliana Gianolio Mauro Botta 《Journal of biological inorganic chemistry》2014,19(2):133-143
A dimeric GdAAZTA-like complex (AAZTA is 6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid) bearing an adamantyl group (Gd2 L1) able to form strong supramolecular adducts with specific hosts such as β-cyclodextrin (β-CD), poly-β-CD, and human serum albumin (HSA) is reported. The relaxometric properties of Gd2 L1 were investigated in aqueous solution by measuring the 1H relaxivity as a function of pH, temperature, and magnetic field strength. The relaxivity of Gd2 L1 (per Gd atom) at 40 MHz and 298 K is 17.6 mM?1 s?1, a value that remains almost constant at higher fields owing to the great compactness and rigidity of the bimetallic chelate, resulting in an ideal value for the rotational correlation time for high-field MRI applications (1.5–3.0 T). The noncovalent interaction of Gd2 L1 with β-CD, poly-β-CD, and HSA and the relaxometric properties of the resulting host–guest adducts were investigated using 1H relaxometric methods. Relaxivity enhancements of 29 and 108 % were found for Gd2 L1–β-CD and Gd2 L1–poly-β-CD, respectively. Binding of Gd2 L1 to HSA (K A = 1.2 × 104 M?1) results in a remarkable relaxivity of 41.4 mM?1 s?1 for the bound form (+248 %). The relaxivity is only limited by the local rotation of the complex within the binding site, which decreases on passing from Gd2 L1–β-CD to Gd2 L1–HSA. Finally, the applicability of Gd2 L1 as tumor-targeting agent through passive accumulation of the HSA-bound adduct was evaluated via acquisition of magnetic resonance images at 1 T of B16-tumor-bearing mice. These experiments indicate a considerable signal enhancement (+160 %) in tumor after 60 min from the injection and a very low hepatic accumulation. 相似文献
4.
Atmospheric nitrogen inputs and losses along an urbanization gradient from Boston to Harvard Forest,MA 总被引:1,自引:0,他引:1
Urbanization alters nitrogen (N) cycling, but the spatiotemporal distribution and impact of these alterations on ecosystems are not well-quantified. We measured atmospheric inorganic N inputs and soil leaching losses along an urbanization gradient from Boston, MA to Harvard Forest in Petersham, MA. Atmospheric N inputs at urban sites (12.3 ± 1.5 kg N ha?1 year?1) were significantly greater than non-urban (5.7 ± 0.5 kg N ha?1 year?1) sites with NH4 + (median value of 77 ± 4 %) contributing thrice as much as NO3 ?. Proximity to urban core correlated positively with NH4 + (R2 = 0.57, p = 0.02) and total inorganic N inputs (R2 = 0.61, p = 0.01); on-road CO2 emissions correlated positively with NO 3 ? inputs (R2 = 0.74, p = 0.003). Inorganic N leaching rates correlated positively with atmospheric N input rates (R2 = 0.61, p = 0.01), but did not differ significantly between urban and non-urban sites (p > 0.05). Our empirical measurements of atmospheric N inputs are greater for urban areas and less for rural areas compared to modeled regional estimates of N deposition. Five of the nine sites had NO 3 ? leached that came almost entirely from nitrification, indicating that the NO3 ? in leachate came from biological processes rather than directly passing through the soil. A significant proportion (17–100 %) of NO 3 ? leached from the other four sites came directly from the atmosphere. Surprisingly, the four sites where atmospheric sources made up the largest proportion of leachate NO3 ? also had relatively low N leaching rates, suggesting that atmospheric N inputs added to terrestrial ecosystems can move to multiple sinks and losses simultaneously, rather than being lost via leaching only after abiotic and biotic sinks have become saturated. This study improves our understanding of atmospheric N deposition and leaching in urban ecosystems, and highlights the need to incorporate urbanization effects in N deposition models. 相似文献
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Chia-Hui Wu Chia-Wen Pen Pei-Yun Wang Shau-Wei Tsai 《Applied microbiology and biotechnology》2013,97(4):1581-1587
In the Candida antarctica lipase B-catalyzed hydrolysis of (R,S)-azolides derived from (R,S)-N-protected proline in water-saturated methyl tert-butyl ether (MTBE), high enzyme activity with excellent enantioselectivity (V S V R ?1 ?>?100) for (R,S)-N-Cbz-proline 1,2,4-triazolide (1) and (R,S)-N-Cbz-proline 4-bromopyrazolide (2) was exploited in comparison with their corresponding methyl ester analog (3). Changing of the substrate structure, water content, solvent, and temperature was found to have profound influences on the lipase performance. On the basis of enzyme activity and enantioselectivity and solvent boiling point, the best reaction condition of using 1 as the substrate in water-saturated MTBE at 45 °C was selected and further employed for the successful resolution of (R,S)-N-Cbz-pipecolic 1,2,4-triazolide (5) and (R,S)-N-Boc-nipecotic 1,2,4-triazolide (9). Moreover, more than 89.1 % recovery of remained (R)-1 is obtainable in five cycles of enzyme reusage, when pH 7 phosphate buffers were employed as the extract at 4 °C. 相似文献
7.
Sebastian A. Stoian Chung-Hung Hsieh Michael L. Singleton Andrea F. Casuras Marcetta Y. Darensbourg Kelsey McNeely Kurt Sweely Codrina V. Popescu 《Journal of biological inorganic chemistry》2013,18(6):609-622
Mössbauer studies of [{μ-S(CH2C(CH3)2CH2S}(μ-CO)FeIIFeI(PMe3)2(CO)3]PF6 (1 OX ), a model complex for the oxidized state of the [FeFe] hydrogenases, and the parent FeIFeI derivative are reported. The paramagnetic 1 OX is part of a series featuring a dimethylpropanedithiolate bridge, introducing steric hindrance with profound impact on the electronic structure of the diiron complex. Well-resolved spectra of 1 OX allow determination of the magnetic hyperfine couplings for the low-spin distal FeI ( $ {\text{Fe}}^{\text{I}} _{\text{ D}} $ Fe D I ) site, A x,y,z = [?24 (6), ?12 (2), 20 (2)] MHz, and the detection of significant internal fields (approximately 2.3 T) at the low-spin ferrous site, confirmed by density functional theory (DFT) calculations. Mössbauer spectra of 1 OX show nonequivalent sites and no evidence of delocalization up to 200 K. Insight from the experimental hyperfine tensors of the FeI site is used in correlation with DFT to reveal the spatial distribution of metal orbitals. The Fe–Fe bond in [Fe2{μ-S(CH2C(CH3)2CH2S}(PMe3)2(CO)4] (1) involving two $ d_{{z^{2} }} $ d z 2 -type orbitals is crucial in keeping the structure intact in the presence of strain. On oxidation, the distal iron site is not restricted by the Fe–Fe bond, and thus the more stable isomer results from inversion of the square pyramid, rotating the $ d_{{z^{2} }} $ d z 2 orbital of $ {\text{Fe}}^{\text{I}} _{\text{ D}} $ Fe D I . DFT calculations imply that the Mössbauer properties can be traced to this $ d_{{z^{2} }} $ d z 2 orbital. The structure of the magnetic hyperfine coupling tensor, A, of the low-spin FeI in 1 OX is discussed in the context of the known A tensors for the oxidized states of the [FeFe] hydrogenases. 相似文献
8.
Rafael Omar Saavedra Díaz Ronan Le Lagadec Alexander D. Ryabov 《Journal of biological inorganic chemistry》2013,18(5):547-555
Cyclometalated RuII derivatives of 2-phenylpyridine (Hphpy) [Ru(phpy)(bpy)2]Cl (1a) and [Ru(phpy)(phen)2]Cl (1b) (bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline) behave as noncompetitive inhibitors of glucose oxidase from Aspergillus niger in the enzyme-catalyzed oxidation of d-glucose by O2 into the corresponding lactone at pH 5.0 and 25 °C. The enzymatic activity has been measured by monitoring the O2 consumption. The inhibition constants K i are 0.036 and 0.017 M for 1a and 1b, respectively, indicating that 1b inhibits the enzymatic activity more efficiently than 1a. The well-known coordination compound [Ru(bpy)3]Cl2 (2) behaves, in contrast, as a competitive inhibitor, with K i = 0.018 M under the same conditions. The monophasic consumption of O2 in the case of 1a, 1b, and 2 is replaced by a distinct two-phase kinetics in the presence of the cyclometalated RuIII compound [Ru(phpy)(bpy)2]Cl2 (3), which was obtained from 1a in the presence of a large excess of H2O2 and the iron TAML activator. Interestingly, the rates of the first and the second phases are influenced by 3 in a different way. The rate of the first phase is noticeably higher in the presence of RuIII, although the dependence is nonmonotonic and maximal acceleration is observed at the lowest loadings of 3. The rate of the second phase decreases monotonically on increasing the concentration of the ruthenium complex in solution. The nonmonotonic action of 3 was confirmed by using the doubly cyclometalated RuIII derivative [Ru(phpy)2(bpy)]Cl. The diverse rate variations induced by 3 accounted for acceleration by RuIII of the O2 reduction by the reduced form of glucose oxidase during the first phase, which ceases after the enzymatic reduction of RuIII to the RuII species, the latter behaving similarly to 1a as the inhibitor of the enzyme. 相似文献
9.
Zuo Peng Li Yeong Hun Song Zia Uddin Yan Wang Ki Hun Park 《Bioorganic & medicinal chemistry》2018,26(3):737-746
Cratoxylum cochinchinense displayed significant inhibition against protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase, both of which are key target enzymes to attenuate diabetes and obesity. The compounds responsible for both enzymes inhibition were identified as twelve xanthones (1–12) among which compounds 1 and 2 were found to be new ones. All of them simultaneously inhibited PTP1B with IC50s of (2.4–52.5?µM), and α-glucosidase with IC50 values of (1.7–72.7?µM), respectively. Cratoxanthone A (3) and γ-mangostin (7) were estimated to be most active inhibitors against both PTP1B (IC50?=?2.4?µM for 3, 2.8?µM for 7) and α-glucosidase (IC50?=?4.8?µM for 3, 1.7?µM for 7). In kinetic studies, all isolated xanthones emerged to be mixed inhibitors of α-glucosidase, whereas they behaved as competitive inhibitors of PTP1B. In time dependent experiments, compound 3 showed isomerization inhibitory behavior with following kinetic parameters: Kiapp?=?2.4?µM; k5?=?0.05001?µM?1?S?1 and k6?=?0.02076?µM?1?S?1. 相似文献
10.
Ruijie Gao Huaxiang Deng Zhengbing Guan Xiangru Liao Yujie Cai 《Annals of microbiology》2017,67(1):65-77
A new α-glucosidase from Shiraia sp. SUPER-H168 under solid-state fermentation was purified by alcohol precipitation and anion-exchange and by gel filtration chromatography. The optimum pH and temperature of the purified α-glucosidase were 4.5 and 60 °C, respectively, using p-nitrophenyl-α-glucopyranoside (α-pNPG) as a substrate. Ten millimoles of sodium dodecyl sulfate, Fe2+, Cu2+, and Ag+ reduced the enzyme activity to 0.7, 7.6, 26.0, and 6.2 %, respectively, of that of the untreated enzyme. The K m, V max, and k cat/K m of the α-glucosidase were 0.52 mM, 3.76 U mg?1, and 1.3?×?104 L s?1 mol?1, respectively. K m with maltose was 0.62 mM. Transglycosylation activities were observed with maltose and sucrose as substrates, while there was no transglycosylation with trehalose. DNA and its corresponding full-length cDNA were cloned and analyzed. The α-glucosidase coding region consisted of a 2997-bp open reading frame encoding a 998-amino acid protein with a 22-amino acid signal peptide; one 48-bp intron was located. The α-glucosidase was a monomeric protein with a predicted molecular mass of 108.2 kDa and a predicted isoelectric point of 5.08. A neighbor-joining phylogenetic tree demonstrated that Shiraia sp. SUPER-H168 α-glucosidase is an ascomycetes α-glucosidase. This is the first report of α-glucosidase from a filamentous fungus that had good glycoside hydrolysis with maltose and α-pNPG, transglycosylation and conversion activity of maltose into trehalose. 相似文献
11.
Four new platinum(II) complexes: PtII L1·H2O (C1, H2 L1 = C20H16N2O2), PtII L2Cl2 (C2, L2 = C22H16N2O2), PtII L3Cl2·H2O (C3, L3 = C20H16N2), PtII L4Cl2·0.4H2O (C4, L4 = C18H14N4) have been synthesized and characterized by using various physico-chemical techniques. The binding interaction of the four platinum(II) complexes C1–C4 with calf thymus (CT)-DNA has been investigated by UV–Vis and fluorescence emission spectrometry. The apparent binding constant (K app) values follow the order: C3 > C1 > C2 > C4. In addition, fluorescence spectrometry of bovine serum albumin (BSA) with the four platinum(II) complexes C1–C4 showed that the quenching mechanism might be a static quenching procedure. For C1–C4, the number of binding sites was about one for BSA and the binding constants follow the order: C3 (7.08 × 105M?1) > C1 (2.82 × 105M?1) > C2 (0.85 × 105M?1) > C4 (0.15 × 105M?1). With the single condition change such as absence of an external agent, the DNA cleavage abilities of C3 exhibit remarkable changes. In addition, the cytotoxicity of C3 in vitro on tumor cells lines (MCF-7, HepG2 and HT29) were examined by MTT and showed better antitumor effects on the tested cells. 相似文献
12.
Tanabe G Otani T Cong W Minematsu T Ninomiya K Yoshikawa M Muraoka O 《Bioorganic & medicinal chemistry letters》2011,21(10):3159-3162
Four analogs with 3′-O-alkyl groups (9a: CH3, 9b: C2H5, 9c: C13H27 or 9d: CH2Ph) instead of the 3′-O-sulfate anion in salacinol (1), a naturally occurring potent α-glucosidase inhibitor, were synthesized by the coupling reaction of 1,4-dideoxy-1,4-epithio-d-arabinitols (18a and 18b) with appropriate epoxides (10a-10d). These analogs showed equal or considerably higher inhibitory activity against rat small intestinal α-glucosidases than the original sulfate (1), and one of them (9d) was found more potent than currently used α-glucosidase inhibitors as antidiabetics. Thus, introduction of a hydrophobic moiety at the C3′ position of this new class of inhibitor was found beneficial for onset of stronger inhibition against these enzymes. 相似文献
13.
Jong-Hyun Jung Dong-Ho Seo James F. Holden Cheon-Seok Park 《Applied microbiology and biotechnology》2014,98(5):2121-2131
The deduced amino acid sequence from a gene of the hyperthermophilic archaeon Pyrococcus sp. ST04 (Py04_0872) contained a conserved glycoside hydrolase family 57 (GH57) motif, but showed <13 % sequence identity with other known Pyrococcus GH57 enzymes, such as 4-α-glucanotransferase (EC 2.4.1.25), amylopullulanase (EC 3.2.1.41), and branching enzyme (EC 2.4.1.18). This gene was cloned and expressed in Escherichia coli, and the recombinant product (P yrococcus sp. ST04 maltose-forming α-amylase, PSMA) was a novel 70-kDa maltose-forming α-amylase. PSMA only recognized maltose (G2) units with α-1,4 and α-1,6 linkages in polysaccharides (e.g., starch, amylopectin, and glycogen) and hydrolyzed pullulan very poorly. G2 was the primary end product of hydrolysis. Branched cyclodextrin (CD) was only hydrolyzed along its branched maltooligosaccharides. 6-O-glucosyl-β-cyclodextrin (G1-β-CD) and β-cyclodextrin (β-CD) were resistant to PSMA suggesting that PSMA is an exo-type glucan hydrolase with α-1,4- and α-1,6-glucan hydrolytic activities. The half-saturation value (K m) for the α-1,4 linkage of maltotriose (G3) was 8.4 mM while that of the α-1,6 linkage of 6-O-maltosyl-β-cyclodextrin (G2-β-CD) was 0.3 mM. The k cat values were 381.0 min?1 for G3 and 1,545.0 min?1 for G2-β-CD. The enzyme was inhibited competitively by the reaction product G2, and the K i constant was 0.7 mM. PSMA bridges the gap between amylases that hydrolyze larger maltodextrins and α-glucosidase that feeds G2 into glycolysis by hydrolyzing smaller glucans into G2 units. 相似文献
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Bienvenu Glinma Sika D. S. Kpoviessi Fernand A. Gbaguidi Coco N. Kapanda Joanne Bero Joëlle Quetin-Leclercq Mansourou Moudachirou Jacques Poupaert Georges C. Accrombessi Emma W. Gachomo Lamine Baba-Moussa Simeon O. Kotchoni 《Molecular biology reports》2014,41(3):1617-1622
Thiosemicarbazones have become one of the promising compounds as new clinical candidates due to their wide spectrum of pharmaceutical activities. The wide range of their biological activities depends generally on their related aldehyde or ketone groups. Here, we report the pharmacological activities of some thiosemicarbazones synthesized in this work. Benzophenone and derivatives were used with N(4)-phenyl-3-thiosemicarbazide to synthesize corresponding five thiosemicarbazones (1–5). Their structures were characterized by spectrometrical methods analysis IR, NMR 1H & 13C and MS. The compounds were then screened in vitro for their antiparasitic activity and toxicity on Trypanosoma brucei brucei and Artemia salina Leach respectively. The selectivity index of each compound was also determined. Four thiosemicarbazones such as 4, 2, 3 and 1 reveal interesting trypanocidal activities with their half inhibitory concentration (IC50) equal to 2.76, 2.83, 3.86 and 8.48 μM respectively, while compound 5 (IC50 = 12.16 μM) showed a moderate anti-trypanosomal activity on parasite. In toxicity test, except compound 1, which showed a half lethal concentration LC50 >281 μM, the others exerted toxic effect on larvae with LC50 of 5.56, 13.62, 14.55 and 42.50 μM respectively for thiosemicarbazones 4, 5, 3 and 2. In agreement to their selectivity index, which is greater than 1 (SI >1), these compounds clearly displayed significant selective pharmaceutical activities on the parasite tested. The thiosemicarbazones 2–5 that displayed significant anti-trypanosomal and cytoxicity activities are suggested to have anti-neoplastic and anti-cancer activities. 相似文献
16.
To understand the chemical behavior of uranyl complexes in water, a bis-uranyl [(phen)(UO2)(μ2–F)(F)]2 (A; phen?=?phenanthroline, μ2?=?doubly bridged) and its hydrated form A?·?(H2O)n (n?=?2, 4 and 6) were examined using scalar relativistic density functional theory. The addition of water caused the phen ligands to deviate slightly from the U2(μ2–F)2 plane, and red-shifts the U–F-terminal and U?=?O stretching vibrations. Four types of hydrogen bonds are present in the optimized hydrated A?·?(H2O)n complexes; their energies were calculated to fall within the range 4.37–6.77 kcal mol-1, comparable to the typical values of 5.0 kcal mol-1 reported for hydrogen bonds. An aqueous environment simulated by explicit and/or implicit models lowers and re-arranges the orbitals of the bis-uranyl complex. Figure
A bis(uranyl) complex [(phen)(UO2)(μ2–F)(F)]2 (A) and its solvated form A?·?(H2O)n were examined using scalar relativistic density functional theory. Hydrogen bonds cause the phen ligand to slightly deviate from the equatorial plane of the uranyl ion, resulting in a pronounced red-shift of the U–F-terminal and U?=?O asymmetric stretching vibrations. The calculated energies fall within 4.4?–6.8 kcal/mol. Explicit and/or implicit aqueous solvation re-arranges the molecular orbitals of the complex 相似文献
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Purple-leaved Ficus lyrata plants produced by overexpressing a grapevine VvMybA1 gene 总被引:1,自引:0,他引:1
Jietang Zhao Zhijian T. Li Juan Chen Richard J. Henny Dennis J. Gray Jianjun Chen 《Plant cell reports》2013,32(11):1783-1793
Key message
This study established an efficient method of regenerating plants of Ficus lyrata and producing purple-leaved F. lyrata plants through genetic transformation using a VvMybA1 gene of grapevine.Abstract
Ficus lyrata, a species with unique violin- or guitar-shaped leaves, was regenerated from leaf-derived calli cultured on Murashige and Skoog (MS) basal medium supplemented with 4.5 μM N-phenyl-N’-1, 2, 3-thiadiazol-5-yl urea (TDZ) and 0.5 μM α-naphthalene acetic acid (NAA). Leaf discs were inoculated with Agrobacterium tumefaciens strain EHA 105 harboring a binary vector DEAT that contains the VvMybA1 gene and neomycin phosphotransferase (npt II) gene and subsequently cultured on the established regeneration medium supplemented with 100 mg l?1 kanamycin. Results showed that 87.5 % of the leaf discs produced kanamycin-resistant callus, and 68.8 % of them produced adventitious shoots. Transgenic plants with three leaf colors including green, green-purple, and purple were produced. Regular and quantitative real-time PCR analyses confirmed the integration of transgenes into the host genome. Semi-quantitative RT-PCR analysis indicated that the VvMybA1 gene was responsible for the purple-colored phenotype. Purple-leaved plants with strong color stability grew vigorously in a greenhouse. This study illustrated the feasibility of using a genetically engineered VvMybA1 gene for drastic modification of leaf color of an important woody ornamental plant. 相似文献19.
Makoto Watanabe Qiaozhi Mao Eka Novriyanti Kazuhito Kita Kentaro Takagi Fuyuki Satoh Takayoshi Koike 《Trees - Structure and Function》2013,27(6):1647-1655
Key message
Elevated CO 2 enhances the photosynthesis and growth of hybrid larch F 1 seedlings. However, elevated CO 2 -induced change of tree shape may have risk to the other environmental stresses.Abstract
The hybrid larch F1 (Larix gmelinii var. japonica × L. kaempferi) is one of the most promising species for timber production as well as absorption of atmospheric CO2. To assess the ability of this species in the future high CO2 environment, we investigated the growth and photosynthetic response of hybrid larch F1 seedlings to elevated CO2 concentration. Three-year-old seedlings of hybrid larch F1 were grown on fertile brown forest soil or infertile volcanic ash soil, and exposed to 500 μmol mol?1 CO2 in a free-air CO2 enrichment system located in northern Japan for two growing seasons. Regardless of soil type, the exposure to elevated CO2 did not affect photosynthetic traits in the first and second growing seasons; a higher net photosynthetic rate was maintained under elevated CO2. Growth of the seedlings under elevated CO2 was greater than that under ambient CO2. We found that elevated CO2 induced a change in the shape of seedlings: small roots, slender-shaped stems and long-shoots. These results suggest that elevated CO2 stimulates the growth of hybrid larch F1, although the change in tree shape may increase the risk of other stresses, such as strong winds, heavy snow, and nutrient deficiency. 相似文献20.
Ya-Jun Wang Bin-Bin Ying Min Chen Wei Shen Zhi-Qiang Liu Yu-Guo Zheng 《World journal of microbiology & biotechnology》2017,33(7):144
A new anti-Prelog short-chain dehydrogenase/reductase (SDR) encoding gene lcsdr was cloned from Lactobacillus composti DSM 18527, and heterologously expressed in Escherichia coli. LcSDR is nicotinamide adenine dinucleotide phosphate (NADPH)-dependent and has a molecular weight of approximately 30 kDa. The optimal pH and temperature were 6.5 and 30?°C, respectively. The maximal reaction rate Vmax was 133.9 U mg?1; the Michaelis–Menten constant K m of LcSDR were 0.345 mM for acetophenone (1a), and 0.085 mM for NADPH. Through introducing an EsGDH-catalyzed NADPH regeneration system, a biocatalytic process for (R)-1-phenylethanol ((R)-1b) was developed with outstanding time–space yield. Under the optimized conditions, 50 g l?1 1a was converted to (R)-1b in 2 h with a yield of 93.8%, enantiomeric excess of product (e.e.p) above 99% and space–time yield of 562.8 g l?1 d?1. 相似文献