Photoluminescence properties and energy transfer in Ce3+/Dy3+ co‐doped Sr3MgSi2O8 phosphors for potential application in ultraviolet white light‐emitting diodes

Sr₃MgSi₂O₈:Ce³⁺, Dy³⁺ phosphors were prepared by a solid‐state reaction technique and the photoluminescence properties were investigated. The emission spectra show not only a band due to Ce³⁺ ions (403 nm) but also as a band due to Dy³⁺ ions (480, 575 nm) (UV light excitation). The photoluminescence properties reveal that effective energy transfer occurs in Ce³⁺/Dy³⁺ co‐doped Sr₃MgSi₂O₈ phosphors, and the co‐doping of Ce³⁺ could enhance the emission intensity of Dy³⁺ to a certain extent by transferring its energy to Dy³⁺. The Ce³⁺/Dy³⁺ energy transfer was investigated by emission/excitation spectra, and photoluminescence decay behaviors. In Sr_2.94MgSi₂O₈:0.01Ce³⁺, 0.05Dy³⁺ phosphors, the fluorescence lifetime of Dy³⁺ (from 3.35 to 27.59 ns) is increased whereas that of Ce³⁺ is greatly decreased (from 43.59 to 13.55 ns), and this provides indirect evidence of the Ce³⁺ to Dy³⁺ energy transfer. The varied emitted color of Sr₃MgSi₂O₈:Ce³⁺, Dy³⁺ phosphors from blue to white were achieved by altering the concentration ratio of Ce³⁺ and Dy³⁺. These results indicate Sr₃MgSi₂O₈:Ce³⁺, Dy³⁺ may be as a candidate phosphor for white light‐emitting diodes. Copyright © 2012 John Wiley & Sons, Ltd.     

外来入侵植物飞机草和本地植物异叶泽兰对大气CO_2浓度升高的响应

大气CO2浓度升高影响外来植物入侵,研究外来入侵植物和本地植物对大气CO2浓度升高响应的差异,有助于准确预测和管理外来植物入侵。基于封顶式CO2生长室,模拟大气CO2浓度变化(对照和700μmol/mol),比较研究了外来入侵植物飞机草(Chromolaena odorata)和本地植物异叶泽兰(Eupatorium heterophyllum)形态、生长、生物量分配和光合特性对大气CO2浓度升高响应的差异。结果表明:(1)在当前大气CO2浓度下,飞机草总生物量、株高、基径和总叶面积高于异叶泽兰,分枝数低于异叶泽兰;CO2浓度升高,飞机的总生物量、株高、基径、分枝数和总叶面积分别增加了92%、41%、60%、325%和148%,高于异叶泽兰的32%、14%、30%、64%和79%,飞机草生长优势进一步提高。(2)无论在高或低CO2浓度下,飞机草根生物量分数(RMF)都低于异叶泽兰,叶生物量分数(LMF)和茎生物量分数(SMF)都高于异叶泽兰;CO2倍增两种植物RMF均降低,LMF和SMF均升高,但这2个参数对CO2倍增响应的种间差异不显著。(3)无论在高或低CO2浓度下,飞机草和异叶泽兰的净光合速率差异均不显著,CO2倍增对两种植物的净光合速率的促进作用相似。上述结果表明,在未来大气CO2浓度升高的条件下,飞机草的入侵性可能提高,入侵危害将加剧。     

Shifts and plasticity of plant leaf mass per area and leaf size among slope aspects in a subalpine meadow

The composition of vegetation on a slope frequently changes substantially owing to the different micro‐environments of various slope aspects. To understand how the slope aspect affects the vegetation changes, we examined the variations in leaf mass per area (LMA) and leaf size (LS) within and among populations for 66 species from 14 plots with a variety of slope aspects in a subalpine meadow. LMA is a leaf economic trait that is tightly correlated with plant physiological traits, while the LS shows a tight correlation with leaf temperature, indicating the strategy of plants to self‐adjust in different thermal and hydraulic conditions. In this study, we compared the two leaf traits between slope aspects and between functional types and explored their correlation with soil variables and heat load. Our results showed that high‐LMA, small‐leaved species were favored in south‐facing slopes, while the reverse was true in north‐facing areas. In detail, small dense‐leaved graminoids dominated the south slopes, while large thin‐leaved forbs dominated the north slopes. Soil moisture and the availability of soil P were the two most important soil factors that related to both LMA and LS, and heat load also contributed substantially. Moreover, we disentangled the relative importance of intraspecific trait variation and species turnover in the trait variation among plots and found that the intraspecific variation contributed 98% and 56% to LMA and LS variation among communities, respectively, implying a large contribution of intraspecific trait plasticity. These results indicate that LMA and LS are two essential leaf traits that affect the adaptation or acclimation of plants underlying the vegetation composition changes in different slope aspects in the subalpine meadow.     

Characterization of the unarmored dinoflagellate Pseliodinium pirum (Ceratoperidiniaceae) from Jiaozhou Bay,China

A strain of Pseliodinium pirum was isolated from Jiaozhou Bay, China, identified based on a recently emended classification, and further characterized for its morphology using light, scanning electron, and transmission electron microscopy, and phylogeny based on SSU and partial LSU rDNA sequences. The pigment composition, life history, and potential effects on aquatic animals were also examined. We observed the typical characteristics of Ceratoperidiniaceae, in which its apical structure complex (ASC) formed a circular loop, and the ASC of our isolate comprised four to five rows of vesicles, and connected with sulcal intrusion. Epifluorescence and transmission electron microscopy revealed a bean‐shaped, centrally located nucleus, with at least 76 chromosomes. Numerous rod‐shaped chloroplasts were in connection to the irregularly shaped pyrenoids. Pigment analysis showed that peridinin was the most abundant among all carotenoids and other pigments. Phylogenetic analyses using maximum likelihood and Bayesian inference indicated that our isolate is conspecific with the entity Cochlodinium cf. helix (accession No. KF245459), but different from Ceratoperidinium, Kirithra, and other unidentified species of the family Ceratoperidiniaceae. Pseliodinium pirum could produce sexual, thin‐walled cyst, with subspherical and spherical shape and smooth surface (without spines or rough projections). The cyst could germinate within 3 days. Bioassays did not show adverse effects of P. pirum on the finfish Oryzias melastigma and the rotifer Brachionus plicatilis, indicating it may not be a harmful species.     

利用卫星追踪颈圈对圈养野生双峰驼野化放归的监测

2012-2014年,通过对甘肃敦煌西湖国家级自然保护区野化放归的两峰野生双峰驼（Camelus ferus）佩带卫星追踪颈圈进行跟踪监测,利用最小凸多边形法和内核法开展了放归生境中野骆驼的活动范围和空间利用研究。研究期间,分别进行了22个月(ID:108444)和9个月(ID:108445)的跟踪监测,获得了3403个(ID:108444) 和1573个(ID:108445)定位成功的GPS位点。野骆驼放归后的前两个月仍存在一定的对圈养环境的依赖,两个月后野骆驼的活动范围开始向外扩展,直至四个月后,基本扩展至整个放养的围栏,活动范围分别从9.5109 km²增加到19.3694 km2 (ID:108444),8.8943 km² 增加到19.4192 km² (ID:108445)。整个监测期间,95% Kernel活动范围分别为7.7181km² (ID:108444) 和 3.0321 km² (ID:108445)。从整个监测期间(ID:108444)的50% Kernel活动范围（0.2811 km²）来看,野骆驼整个放归期间仍然比较依赖原先的圈养环境;野骆驼存在对胡杨疏林的偏好;同时,放归的野骆驼仍然保持了对人的亲近行为。从2013年整年来看,放归野骆驼实际生境利用,春、秋两季范围大,夏、冬两季范围较小。放归的野骆驼不同季节对主要生境的利用也有所不同,最为明显的是夏季,野骆驼活动范围集中在荒漠地区,避开植被多的区域以避免蚊虫叮咬。本研究进一步了解了野骆驼的行为习性及其适应环境的行为对策,为野骆驼圈养种群的科学管理和进一步野化放归提供了理论依据。     

Innovative Approach for Improvement of an Antibiotic-Overproducing Industrial Strain of Streptomyces albus

Working with a Streptomyces albus strain that had previously been bred to produce industrial amounts (10 mg/ml) of salinomycin, we demonstrated the efficacy of introducing drug resistance-producing mutations for further strain improvement. Mutants with enhanced salinomycin production were detected at a high incidence (7 to 12%) among spontaneous isolates resistant to streptomycin (Str^r), gentamicin, or rifampin (Rif^r). Finally, we successfully demonstrated improvement of the salinomycin productivity of the industrial strain by 2.3-fold by introducing a triple mutation. The Str^r mutant was shown to have a point mutation within the rpsL gene (encoding ribosomal protein S12). Likewise, the Rif^r mutant possessed a mutation in the rpoB gene (encoding the RNA polymerase β subunit). Increased productivity of salinomycin in the Str^r mutant (containing the K88R mutation in the S12 protein) may be a result of an aberrant protein synthesis mechanism. This aberration may manifest itself as enhanced translation activity in stationary-phase cells, as we have observed with the poly(U)-directed cell-free translation system. The K88R mutant ribosome was characterized by increased 70S complex stability in low Mg²⁺ concentrations. We conclude that this aberrant protein synthesis ability in the Str^r mutant, which is a result of increased stability of the 70S complex, is responsible for the remarkable salinomycin production enhancement obtained.     

Circular RNA hsa_circ_0004015 regulates the proliferation,invasion, and TKI drug resistance of non-small cell lung cancer by miR-1183/PDPK1 signaling pathway

Circular RNAs (circRNAs) were recently reported to be involved in the pathogenesis of Non-small cell lung cancer (NSCLC), however, the molecular mechanisms of circRNAs in cell proliferation, invasion and TKI drug resistance remain largely undetermined. Here, we identified hsa_circ_0004015 was upregulated in NSCLC tissues, and was associated with the poor overall survival rate of NSCLC patients. Knockdown of hsa_circ_0004015 significantly decreased cell viability, proliferation, and invasion, whereas overexpression exhibited opposed effects in vivo and in vitro. Furthermore, hsa_circ_0004015 could enhance the resistance of HCC827 to gefitinib. In mechanism, hsa_circ_0004015 acted as a sponge for miR-1183, and PDPK1 was revealed to be target gene of miR-1183. Subsequently, functional assays illustrated that the oncogenic effects of hsa_circ_0004015 was attributed to the regulation of miR-1183/PDPK1 axis. In conclusion, circ_0016760/miR-1183/PDPK1 signaling pathway might play vital roles in the tumorigenesis of NSCLC.     

生物反应器及其研究技术进展

阐述了生物反应器设计、放大的新理念及关键技术发展,并在此基础上综述了应用于生物技术产品生产的生物反应器的主要发展趋势,包括以代谢流分析为核心的生物反应器系统、基于计算流体力学模拟技术的传统发酵罐改良、微型生物反应器、动物细胞反应器和酶反应器。     

Saponin 1 Induces Apoptosis and Suppresses NF-κB-Mediated Survival Signaling in Glioblastoma Multiforme (GBM)

Saponin 1 is a triterpeniod saponin extracted from Anemone taipaiensis, a traditional Chinese medicine against rheumatism and phlebitis. It has also been shown to exhibit significant anti-tumor activity against human leukemia (HL-60 cells) and human hepatocellular carcinoma (Hep-G2 cells). Herein we investigated the effect of saponin 1 in human glioblastoma multiforme (GBM) U251MG and U87MG cells. Saponin 1 induced significant growth inhibition in both glioblastoma cell lines, with a 50% inhibitory concentration at 24 h of 7.4 µg/ml in U251MG cells and 8.6 µg/ml in U87MG cells, respectively. Nuclear fluorescent staining and electron microscopy showed that saponin 1 caused characteristic apoptotic morphological changes in the GBM cell lines. Saponin 1-induced apoptosis was also verified by DNA ladder electrophoresis and flow cytometry. Additionally, immunocytochemistry and western blotting analyses revealed a time-dependent decrease in the expression and nuclear location of NF-κB following saponin 1 treatment. Western blotting data indicated a significant decreased expression of inhibitors of apoptosis (IAP) family members,(e.g., survivin and XIAP) by saponin 1. Moreover, saponin 1 caused a decrease in the Bcl-2/Bax ratio and initiated apoptosis by activating caspase-9 and caspase-3 in the GBM cell lines. These findings indicate that saponin 1 inhibits cell growth of GBM cells at least partially by inducing apoptosis and inhibiting survival signaling mediated by NF-κB. In addition, in vivo study also demonstrated an obvious inhibition of saponin 1 treatment on the tumor growth of U251MG and U87MG cells-produced xenograft tumors in nude mice. Given the minimal toxicities of saponin 1 in non-neoplastic astrocytes, our results suggest that saponin 1 exhibits significant in vitro and in vivo anti-tumor efficacy and merits further investigation as a potential therapeutic agent for GBM.