Characteristics of Soil Physicochemical Properties and Microbial Community of Mulberry (Morus alba L.) and Alfalfa (Medicago sativa L.) Intercropping System in Northwest Liaoning.

Medicinal plant intercropping is a new intercropping method. However, as a new intercropping model, the influence of intercropping of alfalfa on microorganisms has not been clarified clearly. In this study, the composition and diversity of microbial communities in alfalfa intercropping were studied, and the differences of bacterial and fungal communities and their relationships with environmental factors are discussed. Intercropping significantly decreased soil pH and significantly increased soil total phosphorus (TP) content, but did not increase soil total carbon (TC) and total nitrogen (TN). Intercropping can increase the relative abundance of Actinobacteria and reduce the relative abundance of Proteobacteria in soil. The relative abundance and diversity of bacteria were significantly correlated with soil pH and TP, while the diversity of fungi was mainly correlated with TC, TN and soil ecological stoichiometry. The bacterial phylum was mainly related to pH and TP, while the fungal phylum was related to TC, TN, C: P and N: P. The present study revealed the stoichiometry of soil CNP and microbial community characteristics of mulberry-alfalfa intercropping soil, clarified the relationship between soil stoichiometry and microbial community composition and diversity, and provided a theoretical basis for the systematic management of mulberry-alfalfa intercropping in northwest Liaoning.

Litter mixing promoted decomposition rate through increasing diversities of phyllosphere microbial communities.

Decomposition of forest litter is an essential process for returning nutrients to the soil, which is crucial for preserving soil fertility and fostering the regular biological cycle and nutrient balance of the forest ecosystem. About 70% of the land-based forest litter is made up primarily of leaf litter. However, research on the complex effects and key determinants of leaf litter decomposition is still lacking. In this study, we examined the characteristics of nutrient release and microbial diversity structure during the decomposition of three types of litter in arid and semi-arid regions using 16S rRNA and ITS sequencing technology as well as nutrient content determination. It was revealed that the nutrient content and rate of decomposition of mixed litters were significantly different from those of single species. Following litter mixing, the richness and diversity of the microbial community on leaves significantly increased. It was determined that there was a significant correlation between bacterial diversity and content (Total N, Total P, N/P, and C/P). This study provided a theoretical framework for investigating the decomposition mechanism of mixed litters by revealing the microbial mechanism of mixed decomposition of litters from the microbial community and nutrient levels.

Effects of Mixed Decomposition of Pinus sylvestris var. mongolica and Morus alba Litter on Microbial Diversity.

Pinus sylvestris var. mongolica is widely planted in China as a windbreak and sand fixation tree. To improve the current situation of large-scale declines of forested areas planted as P. sylvestris var. mongolica monocultures, we investigated the biological and microbial effects of stand establishment using mixed tree species. The interactions during the mixed decomposition of the litter and leaves of different tree species are an important indicator in determining the relationships among species. In this experiment, a method of simulating the mixed decomposition of P. sylvestris var. mongolica and Morus alba litter under P. sylvestris var. mongolica forest was used to determine the total C, total N, and total P contents in the leaf litter, and the microbial structures were determined by using Illumina MiSeq high-throughput sequencing. It was found that with samples with different proportions of P. sylvestris var. mongolica and M. alba litters, the decomposition rate of P. sylvestris var. mongolica × M. alba litter was significantly higher than that of the pure P. sylvestris var. mongolica forest, and the microbial community and composition diversity of litter in a pure P. sylvestris var. mongolica forest could be significantly improved. The possibility of using M. alba as a mixed tree species to address the declines of pure P. sylvestris var. mongolica forest was verified to provide guidance for pure P. sylvestris var. mongolica forests by introducing tree species with coordinated interspecific relationships and creating a mixed forest.

First record of the genus Aneuclis Förster (Hymenoptera, Ichneumonidae) from China.

A new species of the genus Aneuclis Förster, 1869, A. flavopedes Sheng, Zhou Wei, sp.nov. collected from the field of the Research Station of Liaohe-River Plain Forest Ecosystem, Zhangwu, Liaoning Province, China, is described and illustrated. The new species is inserted into the key provided by Khalaim (2004).

A comprehensive review of scaffolding methods in genome assembly.

In the field of genome assembly, scaffolding methods make it possible to obtain a more complete and contiguous reference genome, which is the cornerstone of genomic research. Scaffolding methods typically utilize the alignments between contigs and sequencing data (reads) to determine the orientation and order among contigs and to produce longer scaffolds, which are helpful for genomic downstream analysis. With the rapid development of high-throughput sequencing technologies, diverse types of reads have emerged over the past decade, especially in long-range sequencing, which have greatly enhanced the assembly quality of scaffolding methods. As the number of scaffolding methods increases, biology and bioinformatics researchers need to perform in-depth analyses of state-of-the-art scaffolding methods. In this article, we focus on the difficulties in scaffolding, the differences in characteristics among various kinds of reads, the methods by which current scaffolding methods address these difficulties, and future research opportunities. We hope this work will benefit the design of new scaffolding methods and the selection of appropriate scaffolding methods for specific biological studies.

Identification of novel Lynch syndrome mutations in Chinese patients with endometriod endometrial cancer.

Objective: Lynch syndrome (LS) predisposes patients to early onset endometrioid endometrial cancer (EEC). However, little is known about LS-related EEC in the Chinese population. The aim of this study was to investigate the prevalence of LS and to identify the specific variants of LS in Chinese patients with EEC. Methods: We applied universal immunohistochemistry screening to detect the expression of mismatch repair (MMR) proteins, which was followed by MLH1 methylation analysis to identify suspected LS cases, next-generation sequencing (NGS) to confirm LS, and microsatellite instability (MSI) analysis to verify LS. Results: We collected 211 samples with EEC. Twenty-seven (27/211, 12.8%) EEC cases had a loss of MMR protein expression. After MLH1 methylation analysis, 16 EEC cases were suggested to be associated with LS. Finally, through NGS and MSI analysis, we determined that 10 EEC (10/209, 4.78%) cases were associated with LS. Among those cases, 3 unreported mutations (1 frameshift and 2 nonsense) were identified. MSH6 c.597_597delC, found in 4 patients, is likely to be a founder mutation in China. Conclusions: We demonstrated the feasibility of a process for LS screening in Chinese patients with EEC, by using universal immunohistochemistry screening followed by MLH1 methylation analysis and confirmation through NGS and MSI analysis. The novel mutations identified in this study expand knowledge of LS.

A new species of Campoletis Förster (Hymenoptera, Ichneumonidae) with a key to species known from China, Japan and South Korea.

A new species of the genus Campoletis Förster, 1869, C. deserticola Sheng & Zhou, sp. nov., collected from Zhangwu, Liaoning Province and Songshan National Natural Reserve, Yanqing, Beijing, China, is described and illustrated. A taxonomic key to the species of Campoletis known in China is provided.

Cellular computational generalized neuron network for frequency situational intelligence in a multi-machine power system.

To prevent large interconnected power system from a cascading failure, brownout or even blackout, grid operators require access to faster than real-time information to make appropriate just-in-time control decisions. However, the communication and computational system limitations of currently used supervisory control and data acquisition (SCADA) system can only deliver delayed information. However, the deployment of synchrophasor measurement devices makes it possible to capture and visualize, in near-real-time, grid operational data with extra granularity. In this paper, a cellular computational network (CCN) approach for frequency situational intelligence (FSI) in a power system is presented. The distributed and scalable computing unit of the CCN framework makes it particularly flexible for customization for a particular set of prediction requirements. Two soft-computing algorithms have been implemented in the CCN framework: a cellular generalized neuron network (CCGNN) and a cellular multi-layer perceptron network (CCMLPN), for purposes of providing multi-timescale frequency predictions, ranging from 16.67 ms to 2 s. These two developed CCGNN and CCMLPN systems were then implemented on two different scales of power systems, one of which installed a large photovoltaic plant. A real-time power system simulator at weather station within the Real-Time Power and Intelligent Systems (RTPIS) laboratory at Clemson, SC, was then used to derive typical FSI results.

Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China.

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China.

Seventy-two-hour release formulation of the poorly soluble drug silybin based on porous silica nanoparticles: in vitro release kinetics and in vitro/in vivo correlations in beagle dogs.

The objective of this study was to prepare a 72 h-release formulation of silybin (72 h-SLB) using a combination of solid dispersion, gel matrix and porous silica nanoparticles (PSNs) and to investigate the in vitro/in vivo correlations (IVIVCs). The results of scanning electron microscopy and N(2) adsorption demonstrated that empty PSNs possessed a spherical shape, a highly porous structure, a large specific surface area (385.89 ± 1.12 m(2)/g) and a small pore size (2.74 nm on average). The in vitro dissolution profiles of both 72 h-SLB and silybin-loaded PSNs in different concentrations (0.01, 0.06 and 0.08M) of Na(2)CO(3) solutions revealed that 0.06 M Na(2)CO(3) solution was the optimal medium in which silybin could be released from 72 h-SLB with first-order release kinetics and from PSNs with Higuchi kinetics. Furthermore, the IVIVCs of 72 h-SLB and silybin-loaded PSNs in beagle dogs were also established. Using 0.06 M Na(2)CO(3) solution as the in vitro dissolution medium, a good linear relationship could be achieved for both 72 h-SLB and silybin-loaded PSNs. The findings support the fact that the 72 h-SLB (consisting of solid dispersion, regular gel matrix and PSNs) together with Na(2)CO(3) solution as an in vitro dissolution medium can be developed into a promising formulation for poorly soluble drugs, which enjoys a good IVIVC.

[Soil organic carbon density and its influencing factors of major forest types in the forest region of Northeast China].

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.

Soil bacterial community composition and diversity respond to cultivation in Karst ecosystems.

Soil microorganisms play vital roles in recovering and maintaining the health of ecosystems, particularly in fragile Karst ecosystems that are easily degraded after cultivation. We investigated the composition and diversity of soil bacterial communities, based on RFLP and 16S rDNA sequencing, in a cropland, a naturally revegetated land with former cultivation disturbance and a primeval forest in the subtropical Karst of southwest China. Our results illustrated that Proteobacteria accounted for 44.8% of the 600 tested clones, making it the most dominant phylum observed. This phylum was followed by Acidobacteria and Planctomycetes for the three Karst soils analyzed. Compared with the primeval forest soil, the proportions of Proteobacteria were decreased by 30.2 and 37.9%, while Acidobacteria increased by 93.9 and 87.9%, and the Shannon-Wiener diversity indices and the physicochemical parameters declined in the cropland and the revegetated land, respectively. Among the three soils, the proportion of dominant bacterial phyla and the diversity indices in the revegetated land were similar to the cropland, implying the bacterial community in the cropland was relatively stable, and the after-effects of cultivation were difficult to eliminate. However, similar distributions of the four Proteobacteria subphyla were observed between the revegetated land and the primeval forest soil. Furthermore, the proportion of Rhizobiales belonging to α-Proteobacteria was sharply decreased with cultivation compared to the primeval forest soil, while a small cluster of Rhizobiales recurred with vegetation recovery. These results indicated that although the subphyla of the dominant bacterial phylum had some positive responses to 20 years of vegetation recovery, it is a slow process. Our results suggest that priority should be given to conserve the primeval forest and inoculation of functional microorganisms on the basis of vegetation recovery may be more effective for the restoration of Karst ecosystems after cultivation.

In vitro release and in vitro-in vivo correlation for silybin meglumine incorporated into hollow-type mesoporous silica nanoparticles.

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.

Oral bioavailability of silymarin formulated as a novel 3-day delivery system based on porous silica nanoparticles.

The purpose of this study was to develop porous silica nanoparticles (PSNs) as a carrier to improve oral bioavailability of poorly water-soluble drugs, using silymarin as a model. PSNs were synthesized by reverse microemulsion and ultrasonic corrosion methods. A 3-day release formulation consisting of a silymarin solid dispersion, a hydrophilic gel matrix and silymarin-loaded PSNs was prepared. In vitro release studies indicated that both the silymarin-loaded PSNs and the 3-day release formulation showed a typical sustained-release pattern over a long period, about 72 h. The in vivo studies revealed that the 3-day release formulation gave a significantly higher plasma concentration and larger area under the concentration-time curves than commercial tablets when orally administered to beagle dogs. This implies that the prepared 3-day release formulation significantly enhanced the oral bioavailability of silymarin, suggesting that PSNs can be used as promising drug carriers for oral sustained release systems. Thus providing a technically feasible approach for improving the oral bioavailability and long-term efficacy of poorly soluble drugs.

Incorporating pTGF-ß1/calcium phosphate nanoparticles with fibronectin into 3-dimensional collagen/chitosan scaffolds: efficient, sustained gene delivery to stem cells for chondrogenic differentiation.

The objective of this study was to prepare a 3-dimensional nanoparticle gene delivery system (3D-NGDS) based on collagen/chitosan scaffolds, in which plasmid transforming growth factor beta 1 (TGF-ß1)/calcium phosphate nanoparticles mixed with fibronectin (FN) were used to transfect mesenchymal stem cells (MSCs). Scanning electron microscopy was used to characterise the microstructure of 3-dimensional collagen/chitosan scaffolds. An analysis performed to quantify the TGF-b1 concentrations in MSC cultures revealed that the MSCs transfected with the 3D-NGDS showed remarkably high levels of TGF-b1 over long periods, retaining a concentration of TGF-b1 of approximately 10 ng/mL within two weeks, with the highest level (12.6 ng/mL) being observed on the 6th day. An immunohistochemistry analysis for collagen type II revealed that much higher production of collagen II from the 9th to 15th day was observed in the 3D-NGDS-transfected MSCs than that in MSCs transfected by the Lipofectamine 2000 method. The glycosaminoglycan content of the 3D-NGDS was comparable to those treated with TGF-ß1 as well as TGF-ß1 plus dexamethasone, and was significantly higher than those treated with free plasmid and Lipofectamine 2000. A remarkable type I collagen expression inhibition of the 3D-NGDS at day 21 was observed via ELISA. These results suggested that transfection with the 3D-NGDS could successfully induce MSC chondrogenic differentiation in vitro without dexamethasone. In summary, the 3D-NGDS could be developed into a promising alternative method to transfer exogenous nucleic acid to MSCs in clinical trials.

Efficient gene delivery to mesenchymal stem cells by an ethylenediamine-modified polysaccharide from mulberry leaves.

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.

[Effects of human disturbance on soil aggregates content and their organic C stability in Karst regions].

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.

Encapsulation of plasmid DNA in calcium phosphate nanoparticles: stem cell uptake and gene transfer efficiency.

BACKGROUND: The purpose of this study was to develop calcium phosphate nanocomposite particles encapsulating plasmid DNA (CP-pDNA) nanoparticles as a nonviral vector for gene delivery. METHODS: CP-pDNA nanoparticles employing plasmid transforming growth factor beta 1 (TGF-ß1) were prepared and characterized. The transfection efficiency and cell viability of the CP-pDNA nanoparticles were evaluated in mesenchymal stem cells, which were identified by immunofluorescence staining. Cytotoxicity of plasmid TGF-ß1 and calcium phosphate to mesenchymal stem cells were evaluated by MTT assay. RESULTS: The integrity of TGF-ß1 encapsulated in the CP-pDNA nanoparticles was maintained. The well dispersed CP-pDNA nanoparticles exhibited an ultralow particle size (20-50 nm) and significantly lower cytotoxicity than Lipofectamine™ 2000. Immunofluorescence staining revealed that the cultured cells in this study were probably mesenchymal stem cells. The cellular uptake and transfection efficiency of the CP-pDNA nanoparticles into the mesenchymal stem cells were higher than that of needle-like calcium phosphate nanoparticles and a standard calcium phosphate transfection kit. Furthermore, live cell imaging and confocal laser microscopy vividly showed the transportation process of the CP-pDNA nanoparticles in mesenchymal stem cells. The results of a cytotoxicity assay found that both plasmid TGF-ß1 and calcium phosphate were not toxic to mesenchymal stem cells. CONCLUSION: CP-pDNA nanoparticles can be developed into an effective alternative as a nonviral gene delivery system that is highly efficient and has low cytotoxicity.

[Responses of soil properties to ecosystem degradation in Karst region of northwest Guangxi, China].

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.

[Soil bacterial community structure in primeval forest and degraded ecosystem in Karst region].

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.