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1.
Ying Yong Sheng Tai Xue Bao ; 30(5): 1463-1453, 2019 May.
Artigo em Chinês | MEDLINE | ID: mdl-31107000

RESUMO

Nitrogen deposition and climate warming-drying are the main environmental changes in Northeast China. How they affect forest ecosystems has always been studied in ecological research. In this study, we explored the effects of water stress and nitrogen (N) addition on the short-term (in 55 weeks) growth of seedlings of Pinus koraiensis and Fraxinus mandshurica, two key species in broad-leaved and P. koraiensis mixed forests in temperate zone of Northeast China. Results showed that the responses of seedling growth of P. koraiensis and F. mandshurica to nitrogen addition and water stress were significantly different. P. koraiensis was more sensitive to water stress. In the early stage (in 10 weeks) of water stress, leaf biomass of P. koraiensis significantly decreased while the root biomass increased. Nitrogen addition significantly reduced the root and total biomass of P. koraiensis under water stress. F. mandshurica was more sensitive to N addition. Nitrogen addition rapidly increased the stem, root and total biomass of F. mandshurica. Only sustained water stress could significantly affect the stem, root and total biomass of F. mandshurica. Under continuous water stress and N addition, the biomass contribution of leaves and roots to whole seedling, and the ratio of aboveground to underground biomass of both species tended to be constant, indicating strong self-regulation ability of both species. The results suggested that when drought occurred in the future, P. koraiensis would adopt a "positive" adjustment strategy, while F. mandshurica would adopt a "passive" response. The survival rate and adaptability of P. koraiensis would be higher than F. mandshurica. F. mandshurica would benefit more from N deposition than P. koraiensis. Our results are helpful for predicting the changes of community structure in temperate forest in Northeast China.


Assuntos
Secas , Fraxinus/fisiologia , Nitrogênio/análise , Pinus/fisiologia , Biomassa , China , Humanos , Alocação de Recursos , Plântula
2.
Ying Yong Sheng Tai Xue Bao ; 27(7): 2197-2204, 2016 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-29737127

RESUMO

With secondary forest in the montane region of eastern Liaoning Province as research object, this paper analyzed the spatial distribution and scale effect of Gleason richness index, Simpson dominance index, Shannon diversity index and Pielou evenness index in a 4 hm2 plot. The results showed that spatial distributions of the four diversity indices showed higher spatial heterogeneity. Variance of the four diversity indices varied with increasing scale. Coefficients of variation of the four diversity indices decreased with increasing scale. The four diversity indices of the tree layer were higher than those of the shrub layer, and the variation tendency varied with increasing scale. The results indicated that sampling scale should be taken into account when studying species diversity in the montane region of eastern Liaoning Province.


Assuntos
Biodiversidade , Florestas , China , Dispersão Vegetal , Análise Espacial , Árvores
3.
Ying Yong Sheng Tai Xue Bao ; 24(12): 3333-40, 2013 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-24697048

RESUMO

The five main forest types, i. e. larch forest, birch forest, coniferous mixed forest, broad-leaved mixed forest, and coniferous and broad-leaved mixed forest, with varied age classes (young, mid-aged, pre-mature, and over mature) were selected to investigate the variation of soil organic carbon density in the forest region of Northeast China. Results showed that both soil organic carbon content and density were relatively larger in the top soil layer across the five forest types, decreased gradually with soil depth, and varied insignificantly with either forest type or forest age class. The forest soil carbon density was concentrated in the top 20 cm of soil which accounted for 84.7% - 86.1%, 51.7% - 59.8% and 51.2% - 53.4% of total soil carbon density in the Daxing' an, Xiaoxing' an and Changbai mountains, respectively. The total soil organic carbon density decreased significantly with increasing latitude, which might be attributed mainly to the thickness of soil layers in forest region of Northeast China.


Assuntos
Carbono/análise , Florestas , Solo/química , Ciclo do Carbono , China , Árvores
4.
Int J Nanomedicine ; 7: 1297-311, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22457592

RESUMO

The objective of this study was to investigate the use of cationized Pleurotus eryngii polysaccharide (CPEPS) as a nonviral gene delivery vehicle to transfer plasmid DNA encoding transforming growth factor beta-1 (pTGF-ß1) into mesenchymal stem cells (MSCs) in vitro. Crude P. eryngii polysaccharide was purified, and then cationized by grafting spermine onto the backbone of the polysaccharide. Agarose gel electrophoresis, transmission electron microscopy, and a Nano Sense Zetasizer (Malvern Instruments, Malvern, UK) were used to characterize the CPEPS-pTGF-ß1 nanoparticles. The findings of cytotoxicity analysis showed that when the nanoparticles were formulated with a CPEPS/pTGF-ß1 weight ratio ≥ 10:1, a greater gel retardation effect was observed during agarose gel electrophoresis. The CPEPS-pTGF-ß1 nanoparticles with a weight ratio of 20:1, respectively, possessed an average particle size of 80.8 nm in diameter and a zeta potential of +17.4 ± 0.1 mV. Significantly, these CPEPS-pTGF-ß1 nanoparticles showed lower cytotoxicity and higher transfection efficiency than both polyethylenimine (25 kDa) (P = 0.006, Student's t-test) and Lipofectamine(TM) 2000 (P = 0.002, Student's t-test). Additionally, the messenger RNA expression level of TGF-ß1 in MSCs transfected with CPEPS-pTGF-ß1 nanoparticles was significantly higher than that of free plasmid DNA-transfected MSCs and slightly elevated compared with that of Lipofectamine 2000-transfected MSCs. Flow cytometry analysis demonstrated that 92.38% of MSCs were arrested in the G1 phase after being transfected with CPEPS-pTGF-ß1 nanoparticles, indicating a tendency toward differentiation. In summary, the findings of this study suggest that the CPEPS-pTGF-ß1 nanoparticles prepared in this work exhibited excellent transfection efficiency and low toxicity. Therefore, they could be developed into a promising nonviral vector for gene delivery in vitro.


Assuntos
Células-Tronco Mesenquimais/fisiologia , Nanopartículas/química , Plasmídeos/administração & dosagem , Plasmídeos/genética , Pleurotus/química , Polissacarídeos/administração & dosagem , Transfecção/métodos , Fator de Crescimento Transformador beta1/genética , Análise de Variância , Cátions/química , Sobrevivência Celular/efeitos dos fármacos , DNA/administração & dosagem , DNA/química , DNA/genética , Citometria de Fluxo , Vetores Genéticos/genética , Lipídeos , Tamanho da Partícula , Polissacarídeos/química , RNA Mensageiro/análise , RNA Mensageiro/genética , Espermina/química , Fator de Crescimento Transformador beta1/metabolismo
5.
Int J Nanomedicine ; 7: 753-62, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22393284

RESUMO

BACKGROUND: The purpose of this study was to develop a sustained drug-release model for water-soluble drugs using silica nanoparticles. METHODS: Hollow-type mesoporous silica nanoparticles (HMSNs) were prepared using Na(2)CO(3) solution as the dissolution medium for the first time. The water-soluble compound, silybin meglumine, was used as the model drug. The Wagner-Nelson method was used to calculate the in vivo absorption fraction. RESULTS: The results of transmission electron microscopy and nitrogen adsorption revealed that the empty HMSNs had uniformly distributed particles of size 50-100 nm, a spherical appearance, a large specific surface area (385.89 ± 1.12 m(2)/g), and ultralow mean pore size (2.74 nm). The highly porous structure allowed a large drug-loading rate (58.91% ± 0.39%). In 0.08 M Na(2)CO(3) solution, silybin meglumine-loaded HMSNs could achieve highly efficacious and long-term sustained release for 72 hours in vitro. The results of in vitro-in vivo correlation revealed that HMSNs in 0.08 M Na(2)CO(3) solution had a correlation coefficient R(2) value of 0.9931, while those of artificial gastric juice and artificial intestinal juice were only 0.9287 and 0.7689, respectively. CONCLUSION: The findings of in vitro-in vivo correlation indicate that HMSNs together with Na(2)CO(3) solution could achieve an excellent linear relationship between in vitro dissolution and in vivo absorption for 72 hours, leading to a promising model for sustained release of water-soluble drugs.


Assuntos
Meglumina/química , Meglumina/farmacocinética , Nanopartículas/química , Dióxido de Silício/química , Silimarina/química , Silimarina/farmacocinética , Absorção , Análise de Variância , Animais , Cães , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Suco Gástrico/metabolismo , Concentração de Íons de Hidrogênio , Modelos Lineares , Masculino , Modelos Biológicos , Tamanho da Partícula , Porosidade , Silibina
6.
Small ; 8(3): 441-51, 2012 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-22213679

RESUMO

This study investigates the use of a natural polysaccharide isolated from mulberry leaves as a nonviral gene vector. Ethylenediamine is chemically grafted to the backbone of a polysaccharide from mulberry leaves (MPS) to acquire nucleic acid binding affinity. A particle-size observation indicates that the cationic mulberry leaf polysaccharide (CMPS) can efficiently combine with plasmid transforming growth factor ß1 (TGF-ß1) to form nanoscaled particles. In addition, the electrophoresis assay indicates a retarded plasmid migration when the CMPS/pTGF-ß1 weight ratio is increased to 30:1. The in vitro cell transfection experiment is performed based on bone marrow mesenchymal stem cells (MSCs) derived from rat femurs and tibias, and the findings reveal that the complex with a CMPS/pTGF-ß1 weight ratio of 50:1 exhibits the highest cell transfection effect, which is significantly higher than that of branched poly(ethyleneimine) (PEI) (25 kDa; p = 0.001, Student's t-test) and slightly higher than Lipofectamine 2000. Moreover, the cytotoxicity assay also demonstrates that all of these tested complexes and the plasmid TGF-ß1 are nontoxic to mesenchymal stem cells (MSCs). The results of the living cell imaging confirm that more of the CMPS/plasmid TGF-ß1 nanoparticles can be taken up and at a faster rate by the MSCs than by the positive control Lipofectamine 2000; these data are consistent with the transfection efficiency data. Together, these results suggest that the CMPS/pTGF-ß1 nanoparticle can potentially be developed into a promising alternative for the transfer of therapeutic genes into cells.


Assuntos
Etilenodiaminas/química , Técnicas de Transferência de Genes , Células-Tronco Mesenquimais/metabolismo , Morus/metabolismo , Folhas de Planta/metabolismo , Polissacarídeos/química , Animais , Cátions , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Reagentes para Ligações Cruzadas/farmacologia , Ensaio de Desvio de Mobilidade Eletroforética , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Morus/efeitos dos fármacos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Folhas de Planta/efeitos dos fármacos , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Transfecção , Fator de Crescimento Transformador beta1/farmacologia
7.
Ying Yong Sheng Tai Xue Bao ; 22(4): 971-8, 2011 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-21774320

RESUMO

Taking the primary forest land (PF), natural restoration land (NR), grazing grassland burned annually in winter (GB), and maize-sweet potato cropland (MS) in Karst regions of Northwest Guangxi as test objects, this paper studied the soil aggregates content and their organic C stability in the four ecosystems under different human disturbance patterns. The soil water-stable aggregates (>0.25 mm) content in PF, NR, and GB accounted for more than 70%, while that in MS was only 37%. The destruction rate of soil aggregates structure in the four ecosystems decreased in the sequence of MS (54.9%) > GB (23.2%) > NR (9.8%) and PF (9.6%), with significant differences among them (P<0.05). With increasing incubation time, the mineralization rate of soil aggregate organic C decreased after an initial increase and kept stable after 20 days, and increased with decreasing aggregate size. In the same size aggregates, the mineralization rate of organic C in the four ecosystems increased in the sequence of MS < GB and NR < PF. In PF, the mineralization ratio of soil organic C was 1.7% - 3.8%, being significantly higher than that in NR, GB, and MS. The cumulative mineralization amount of soil organic C had the same change trend with the mineralization rate. The contents of soil organic C and aggregate organic C were significantly positively correlated with the mineralization rate and cumulative mineralization amount of organic C, respectively, and significantly negatively correlated with the mineralization ratio of organic C.


Assuntos
Carbono/análise , Produtos Agrícolas/crescimento & desenvolvimento , Atividades Humanas , Solo/química , Árvores/crescimento & desenvolvimento , Agricultura/métodos , China , Ecossistema , Monitoramento Ambiental/métodos , Ipomoea batatas/crescimento & desenvolvimento , Compostos Orgânicos/análise , Poaceae/crescimento & desenvolvimento , Solo/análise , Zea mays/crescimento & desenvolvimento
8.
Ying Yong Sheng Tai Xue Bao ; 21(5): 1308-14, 2010 May.
Artigo em Chinês | MEDLINE | ID: mdl-20707118

RESUMO

Four typical ecosystems, i.e., maize-sweet potato rotational cultivated land (KMS), grazing grassland burned annually in winter (KGB), natural restoration land (KNR), and primary forest land (KPF), in Karst region of northwest Guangxi were selected to investigate the responses of soil nutrients (C, N and P), soil microbial biomass, and soil structure to the degradation of ecosystem. The contents of soil organic C, total N and P, and soil microbial biomass C, N, and P were significantly higher in KPF than in KMS, KGB, and KNR (P < 0.01). In the latter three degraded ecosystems, the contents of soil organic C and total N were in the sequence of KNR>KGB> KMS but the difference was not significant, soil total P content in KMS (0.87 g x kg(-1)) was 2.07 and 9.67 times of that in KNR and KGB, respectively (P < 0.01), and soil microbial biomass C, N and P contents were significantly higher in KGB and KNR than in KMS (P < 0.05). The soil microbial biomass C was significantly higher in KGB than in KNR (P < 0.05), but there were no significant differences in soil microbial biomass N and P between the two ecosystems. These results illustrated that the reduction of human activity could induce a slight increase of soil organic C in Karst degraded ecosystems, and proper grazing and natural restoration could be the feasible modes for the restoration of degraded ecosystem. Soil microbial biomass was more sensitive in response to the change of ecosystem, being able to be used as a sensitive indicator to reflect the change of degraded ecosystem in Karst region. In KPF, KNR, and KGB, soil water-stable macro-aggregates (> 0.25 mm) accounted for more than 70%, and dominated by >2 mm aggregates; while in KMS, soil water-stable macro-aggregates only occupied 40.34%, and dominated by 2-0.25 mm aggregates. The destruction rate of soil structure in KMS, KGB, KNR, and KPF was 51.62%, 23.48%, 9.09%, and 9.46%, respectively (P < 0.05), indicating that human disturbance or farming practice destroyed soil macro-aggregates, and made the destruction rate of soil structure increased. To reduce human disturbance and implement natural rehabilitation would be the suitable ecological restoration strategy in Karst region.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Ecossistema , Poaceae/crescimento & desenvolvimento , Solo/análise , Árvores/crescimento & desenvolvimento , China , Monitoramento Ambiental/métodos , Ipomoea batatas/crescimento & desenvolvimento , Zea mays/crescimento & desenvolvimento
9.
Ying Yong Sheng Tai Xue Bao ; 20(4): 863-71, 2009 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-19565768

RESUMO

By using PCR-RFLP, this paper studied the 16S rDNA gene diversity and phylogenesis of soil bacteria in primeval forest and degraded ecosystem in Karst region of Northwest Guangxi. More genotypes and higher diversity index were observed in the soil of primeval forest than in that of degraded ecosystem, and only two common genotypes were observed in the two soils. A clone from each genotype was randomly selected as representative for sequencing. The obtained 16S rDNA gene sequences had a similarity of 87%-100% with those in the GenBank (www. ncbi. nlm. nih. gov), and more than half of them had a similarity lower than 97%, being of new species. Based on phylogenetic analysis, the bacteria in the two soils were classified into 10 groups, with 5 groups in common. The dominant bacterial groups in the two soils differed obviously. In primeval forest soil, the dominant group was Proteobacteria, which had 39 genotypes, occupying 58.0% of all the clones; while in the soil of degraded ecosystem, the dominant groups were Acidobacteria and Proteobacteria, which had 19 and 15 genotypes, occupying 32.5% and 30.5% of all the clones, respectively. In the soil of degraded ecosystem, Proteobacteria group decreased while Acidobacteria group increased markedly, compared with those in primeval forest soil. Soil physical and chemical properties and environmental factors should be responsible for the difference of soil bacterial community between the two soils.


Assuntos
Bactérias/classificação , Ecossistema , Microbiologia do Solo , Solo/análise , Árvores/crescimento & desenvolvimento , Bactérias/genética , Bactérias/isolamento & purificação , China , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , DNA Ribossômico/genética , Proteobactérias/genética , Proteobactérias/isolamento & purificação , Árvores/microbiologia
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