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Background To summarize the clinical, genotype and olfactory characteristic in patients with 11C-Pittsburgh compound B (11C-PIB)-positive cognitive impairment. Methods Twenty-seven patients with 11C-PIB-positive cognitive impairment, including 19 patients with Alzheimer's disease (AD) and 8 patients with mild cognitive impairment (MCI), were recruited from January 2015 to February 2016 in Tianjin Huanhu Hospital. The clinical, genotype and olfactory profiles were retrospectively analyzed. Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and Clock Drawing Test (CDT), Neuropsychiatric Inventory (NPI), Activity of Daily Living Scale (ADL), and Hamilton Depression Scale-21 (HAMD-21) were used to evaluate cognitive function, behavioral and psychological symptoms, activities of daily living, and symptoms of depression, respectively. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine ApoE genotype, and T&T olfactometer was used to test threshold of detection and recognition. Results Compared with MCI patients, AD patients had lower MMSE score (P = 0.000), orientation to time (P = 0.031), short-term memory (P = 0.021), recall (P = 0.009), calculation (P = 0.000), repetition (P = 0.038), reading (P = 0.021), writing (P = 0.002), visual-spatial ability (P = 0.039), MoCA score (P = 0.000) and CDT score (P = 0.020), and higher ADL score (P = 0.000). But there was no significant difference in orientation to place, naming, comprehension, NPI score and HAMD-21 score between 2 groups (P > 0.05, for all). There were no statistical differences in incidence of olfactory dysfunction, threshold of detection and recognition between 2 groups (P > 0.05, for all). There were statistical differences in the incidence of olfactory disorders among different ApoE genotypes (Fisher's exact probability: P = 0.000). To further evaluate the effect of ApoEε4 allele on the olfactory function, subjects were additionally dichotomized according to the presence or absence of at least one ApoEε4 allele. Comparing with the subjects without ApoEε4 allele, the olfactory function decreased significantly in those with ApoEε4 allele (0/11 vs. 12/13; Fisher's exact probability: P = 0.000). Conclusions The patients with 11C-PIB-positive cognitive impairment (AD and MCI) had significant olfactory disturbance, which was related to ApoEε4 allele. The assessment of clinical, genotype and olfactory characteristic was helpful in early diagnosis of AD patients. [ABSTRACT FROM AUTHOR]

China's Sloping Land Conversion Program (SLCP) was designed to restore perennial plant cover on sloping land in western China, in part to protect the Three Gorges Reservoir (TGR). In this study, we examined use of white mulberry ( Morus alba L.) in the SLCP to protect water quality and conserve soil. We established nine runoff monitoring plots divided among three categories (vegetable farming, fallow control, and mulberry plantation) on a bank of the Liangtan River situated at the western margin of the TGR. The land had been used previously by farmers for growing vegetables. We found that soil loss and surface water runoff were lowest in the mulberry plots and highest in the vegetable plots. We used inductively coupled plasma atomic emission spectroscopy (ICP-AES) to assess the concentration of selected heavy metal pollution indicators (Zn, Hg, As, Ni, Pb, Cr, Cd, and Cu) in the monitoring plot soils at the beginning of the experiment in May 2009. The heavy metals were assessed again at the end of the experiment in October 2012, and we found that the concentrations of these pollutants had been reduced in all fallow and mulberry plots, and to the greatest extent in the mulberry plots. We found that levels of Hg, Pb, and Cu increased in the vegetable plots. For these reasons, we conclude that riparian mulberry plantations are useful for reducing rapid runoff of storm water, conserving soil, and sequestering heavy metal pollutants in the TGR region. [ABSTRACT FROM AUTHOR]

Grass cover may improve soil environmental conditions in apple orchards. However, the mechanisms for how the soil microbial community changes after cover grass treatments are not well understood. In this study, we analyzed soil properties, microbial community diversity and composition in an apple orchard after being covered with native wild grasses for 3 years on the Loess Plateau, China. The ratios of cover grass were 0% (no cover, NC), 20% (low-intensity cover, LIC), 40% (moderate-intensity cover, MIC1), 60% (moderate-intensity cover, MIC2) and 80% (high-intensity cover, HIC). Meanwhile, the relationships between soil nutrients, cover grass properties, and microbial communities was analyzed by redundancy analysis and Pearson correlations. The results showed that cover grass altered the bacterial community composition, and significant changes at the phylum level were mainly caused by Proteobacteria, Bacteroidetes and Chloroflexi. Compared with NC, the abundance of Proteobacteria was lower in LIC, and the abundance of Bacteroidetes was lower in LIC, MIC1 and MIC2, while that of Chloroflexi was higher in LIC. LIC and MIC1 were the only cover grass intensities that altered the soil fungal community composition; there were no significant differences at the phylum level. The changes in the soil microbial community at the given phyla may be related to the change in soil available nitrogen content caused by cover grass. Here, we demonstrate that cover grass changed the soil microbial community, and the changes may be attributed to the given phyla in the bacterial community; soil copiotrophic groups (e.g., Proteobacteria and Bacteroidetes) were found to be at lower abundance in the low-intensity cover grass. [ABSTRACT FROM AUTHOR]

Changes in soil environmental factors and microbial communities of a precious tree species (Ormosia hosiei) plantation with different forest ages are still unclear. Obtaining this information can provide a theoretical basis for scientific forest management. Ormosia hosiei plantations of varying ages (7, 20, and 45 years old) were targeted in Zhejiang Province, China. We collected surface soil (0–20 cm) and analysed the diversity and structural characteristics of soil microbial communities by high-throughput sequencing. Redundancy analysis (RDA) and Spearman correlation analysis revealed soil environmental factors that cause differences in the microbial communities. The soil bacterial community diversity was not significantly affected by stand age, while the Chao and Ace indexes of the fungal community at 20 and 45 years were markedly higher than those at 7 years. The abundance of Proteobacteria in the 45 years was lower than those at 7 and 20 years, while the abundance of Actinobacteria at 7 years was lower than those at 20 and 45 years, and the abundance of Basidiomycota gradually increased with increasing stand age. The RDA and correlation analysis indicated that the soil microbial biomass carbon (MBC), bulk density (SBD), total porosity (STP), and total potassium (TK) were key factors that affected the bacterial communities and had a significant correlation with Actinobacteria. Soil temperature (T), available phosphorus (AP) and forest litter (FL) affected the fungal communities and had a significant correlation with Basidiomycota. In conclusion, forest age did not affect bacterial diversity, but the soil fungal community of the O. hosiei plantation in the middle-aged forest (20 years old) had the highest diversity; there were obvious differences in the composition and structure of soil microorganisms between different forest ages, which may be attributed to the phyla present (e.g., Proteobacteria , Actinobacteria , and Basidiomycota), which may be caused by differences in T, SBD, STP, AP, TK, MBC, and FL. • Forest age obviously changed the soil fungal community diversity. • The differences of soil microorganisms between different forest ages may be attributed to the phyla present. • Soil copiotrophic bacteria had the highest value at the middle-age forest. [ABSTRACT FROM AUTHOR]

Close-to-nature forest management (CNFM), structure-based forest management (SBFM), and secondary forest comprehensive silviculture (SFCS) are three forest management methods that have been promoted in China. Unfortunately, changes to the canopy structure and understory light characteristics after forest management remain unclear. We compared the canopy structure and light characteristics of a natural Quercus aliena var. acuteserrata forest under the four management methods of CNFM, SBFM, SFCS and unmanaged control (CK) after four years of using the WinScanopy instrument. The results suggest that (1) the leaf area index (LAI) values in the CNFM and SBFM were higher than that in the CK, the mean leaf angle (MLA) value in the SBFM was significantly lower than that in the CK. (2) The values of total under radiant energy (TU) and directed radiant energy (Dir) in the SFCS were significantly higher than that in the CK, while the values of diffused radiant energy (Dif) in the CNFM and SBFM were significantly lower than that in the CK. The extinction coefficient (EC) value in three forest management measure was significantly lower than that in the CK. (3) The canopy structure was sensitive to changes in tree crowding, and the light characteristics were sensitive to changes in forest layer numbers, LAI and CO , which explained 81.19% and 94.88% of the total variations in the canopy structure and light characteristics, respectively. Thus, CNFM and SBFM altered the canopy structure, which may be attributed to the LAI that was influenced by tree crowding, and the three forest treatments altered the understory light environment, which may be influenced mainly by the canopy structure. CNFM and SBFM increased the leaf area index of the stand and improved the understory light environment in a natural Quercus aliena var. acuteserrata forest. [ABSTRACT FROM AUTHOR]

Microorganisms provide ecosystem services, such as decomposition and mineralization processes in forest soils. Quercus aliena var. acuteserrata and Larix kaempferi are the main natural forest and planted forest, respectively, in the national nature reserve of the Xiaolongshan Mountains of China. Understanding the composition and structure of soil microbial communities under these two typical vegetation types is critical for achieving effective management and sustainable utilization of the forest vegetation in the Xiaolongshan Mountain region. In this study, we analysed and compared the soil microbial communities of the Q. acuteserrata natural forest and L. kaempferi planted forest using high-throughput sequencing technology, and cultivated land soil samples were selected as controls. The results indicated that soil nutrient contents and stoichiometric ratios (organic carbon to total nitrogen ratio (C:N), organic carbon to total phosphorus ratio (C:P) and nitrogen to phosphorus ratio (N:P)) were higher in the natural forest than in the planted forest and were lowest in the cultivated land. The soil bacterial community in the Q. acuteserrata natural forest had lower diversity indices than that in the L. kaempferi planted forest and cultivated land, and the soil fungal community in the Q. acuteserrata natural forest had higher diversity indices than that in the cultivated land. Proteobacteria was more abundant in the natural forest soil with higher nutrient levels, and Acidobacteria was more abundant in the plantation forest soil with lower nutrient levels. Ascomycota abundance was lowest in the natural forest, and Basidiomycota abundance was lowest in the plantation forest. Microbial composition was sensitive to soil nutrients and the stoichiometric ratio, which explained 82.67% and 70.72% of the total variations in the soil bacterial and fungal community composition, respectively. There were significant differences in soil microbial community composition and structure between the natural forest and planted forest, and these changes were influenced by soil nutrient conditions. Total phosphorus (TP) may be an important factor regulating microbial community structure in different vegetation soil types. • There was significant differences in microbial communities between different vegetation types. • Changes in microbial community between the natural and planted forest were driven by Proteobacteria , Acidobacteria , Ascomycota and Basidiomycota. • TP may be an important factor regulating microbial community structure in different vegetation-type soils. [ABSTRACT FROM AUTHOR]

Soil microbes play important roles in the nutrient cycles and energy flows of the soil ecosystem. Bupleurum chinense has long been widely cultivated on piedmont farmland in the Xiaolongshan Mountain region; however, the piedmont farmland that was formerly planted with Bupleurumchinense has now been planted with seedlings of Pinus tabulaeformis , a species that has recently been promoted widely in the region. Changes in the composition of the soil microbial community after planting with P. tabulaeformis are not well understood. In this study, using high-throughput sequencing technology, we investigate the soil microbial community of four year old P. tabulaeformis and B.chinense plantations in the Xiaolongshan Mountain region. Furthermore, the response of the soil microbial community to the changes in soil properties was analysed. The soil organic matter (SOM) and available phosphorus (AP) contents were lower in P. tabulaeformis plantations compared with B.chinense plantations. The soil fungal community in P.tabulaeformis plantations had higher diversity indices than that in B.chinense plantations. With respect to the dominant bacterial groups, Proteobacteria had lower relative abundance in P. tabulaeformis soil than in B.chinense soil, and Chloroflexi had higher relative abundance in P. tabulaeformis soil than in B.chinense soil. For the dominant fungal groups, Ascomycota was less abundant in P. tabulaeformis soil than in B.chinense soil. Redundancy analysis (RDA) showed that the SOM significantly correlated with soil fungal communities. These findings suggest that soil nutrients of the cultivated land were decreased in plantations of P. tabulaeformis 4 years after planting. Pinustabulaeformis did not significantly affect soil bacterial communities; however, the changes in the soil fungal communities of both Pinustabulaeformis and Bupleurumchinense plantations may be attributed to the phyla present (Ascomycota), which were primarily affected by soil organic matter in the Xiaolongshan Mountain region. • Soil nutrients were decreased in plantations of Pinus tabulaeformis 4 years after planting. • Pinus tabulaeformis had significant influence on soil fungal diversity. • The changes in the soil fungal communities may be attributed to the phyla present (Ascomycota), and which are correlated with changes in the soil organic matter. [ABSTRACT FROM AUTHOR]