Identification of highly reliable risk genes for Alzheimer's disease through joint-tissue integrative analysis.

Numerous genetic variants associated with Alzheimer's disease (AD) have been identified through genome-wide association studies (GWAS), but their interpretation is hindered by the strong linkage disequilibrium (LD) among the variants, making it difficult to identify the causal variants directly. To address this issue, the transcriptome-wide association study (TWAS) was employed to infer the association between gene expression and a trait at the genetic level using expression quantitative trait locus (eQTL) cohorts. In this study, we applied the TWAS theory and utilized the improved Joint-Tissue Imputation (JTI) approach and Mendelian Randomization (MR) framework (MR-JTI) to identify potential AD-associated genes. By integrating LD score, GTEx eQTL data, and GWAS summary statistic data from a large cohort using MR-JTI, a total of 415 AD-associated genes were identified. Then, 2873 differentially expressed genes from 11 AD-related datasets were used for the Fisher test of these AD-associated genes. We finally obtained 36 highly reliable AD-associated genes, including APOC1, CR1, ERBB2, and RIN3. Moreover, the GO and KEGG enrichment analysis revealed that these genes are primarily involved in antigen processing and presentation, amyloid-beta formation, tau protein binding, and response to oxidative stress. The identification of these potential AD-associated genes not only provides insights into the pathogenesis of AD but also offers biomarkers for early diagnosis of the disease.

[Vertical distribution patterns of nitrogen, phosphorus, and potassium in Chinese pine forest soils developed from different parent materials in Songshan Mountain Nature Reserve, Beijing of China].

Taking the soils developed from two kinds of parent materials (granite and limestone) under Pinus tabulaeformis forest at the same altitude in Songshan Mountain Nature Reserve of Beijing as test objects, this paper studied the vertical distribution patterns of soil total nitrogen, available phosphorus, and available potassium. The soil developed from granite had the total nitrogen, available phosphorus, and available potassium contents being 1.61-2. 35 g kg-1, 5. 84-10.74 mg kg- 1, and 39.33-93.66 mg kg-1, while that developed from limestone had the total nitrogen, available phosphorus, and available potassium contents being 1. 69 -2. 36 g kg-1, 4.45-8.57 mg . kg-1, and 60.66-124.00 mg kg-1, respectively. The total nitrogen, available phosphorus, and available potassium contents in the two soils were the highest in 0-10 cm layer, decreased with increasing depth, and had significant differences between different layers, showing that the soil total nitrogen, available phosphorus, and available potassium had a strong tendency to accumulate in surface layer. Such a tendency was more obvious for the soil developed from limestone. The paired t-test for the two soils indicated that the total nitrogen content in different layers had no significant difference, whereas the available phosphorus content in 0-10 cm layer and the available potassium content in 10-20 cm layer differed significantly.

[Effects of water-nitrogen coupling on leaf nutrient contents of triploid Populus tomentosa clone BT17].

To understand the coupling effect of water and nitrogen on the leaf nutrient contents of Populus tomentosa and to search for an optimal combination of water and nitrogen for P. tomentosa, a field experiment with randomized block design (3 levels of irrigation water and 4 levels of fertilizer nitrogen) was conducted in a two-year-old P. tomentosa clone BT17 plantation in the nursery of Weixian County, Hebei Province of North China from 2007 to 2009. The N, P and K contents in BT17 leaves differed significantly among seasons, with the order of spring > summer > autumn, and had significant differences among the 12 treatments, being the highest in the treatment 75% of field capacity and 160 g per plant of N application rate. The coupling of water and nitrogen had positive effects on the leaf N, P, and K contents, and thus, more attention should be paid to this coupling effect in the management of P. tomentosa. The leaf nutrient contents had different responses to water and nitrogen. The leaf N and K contents were more affected by soil water content, while the leaf P content was more affected by N application rate.