Investigation of the Relationship between Apolipoprotein E Alleles and Serum Lipids in Alzheimer's Disease: A Meta-Analysis.

Prior studies have yielded mixed findings concerning the association between apolipoprotein E(APOE)-ε4 and serum lipids in patients with Alzheimer's disease (AD) and healthy individuals. Some studies suggested a relationship between APOEε4 and serum lipids in patients with AD and healthy individuals, whereas others proposed that the APOEε4 allele affects lipids only in patients with AD. Our study aimed to investigate whether APOE alleles have a distinct impact on lipids in AD. We conducted a comprehensive search of the PubMed and Embase databases for all related studies that investigate APOE and serum lipids of AD from the inception to 30 May 2022. Elevated total cholesterol (TC) and low-density lipoprotein (LDL) levels were found in APOEε4 allele carriers compared with non-carriers. No significant differences were found for high-density lipoprotein (HDL) and triglyceride (TG) levels in APOEε4 allele carriers compared to non-carriers. Notably, elevated TC and LDL levels showed considerable heterogeneity between patients with AD and healthy controls. A network meta-analysis did not find a distinct effect of carrying one or two APOEε4 alleles on lipid profiles. Higher TC and LDL levels were found in APOEε4 allele carriers compared with non-carriers, and the difference was more significant in patients with AD than in healthy controls.

Artificial Selection of Gn1a Plays an Important role in Improving Rice Yields Across Different Ecological Regions.

BACKGROUND: Rice is one of the most important crops, and it is essential to improve rice productivity to satisfy the future global food supply demands. Gn1a (OsCKX2), which encodes cytokinin oxidase/dehydrogenase, plays an important role in regulating rice grain yield. RESULTS: In this study, we analyzed the genetic variation of Gn1a, which influences grain yield through controlling the number of spikelets in rice. The allelic variations in the promoter, 5' untranslated region (UTR) and coding sequence (CDS) of Gn1a were investigated in 175 cultivars and 21 wild rice accessions. We found that Gn1a showed less sequence variation in the cultivars, but exhibited significant nucleotide diversity in wild rice. A total of 14 alleles, named AP1 to AP14, were identified in the cultivars based on the amino acid divergence of GN1A. Association analysis revealed that the number of spikelets and grain yield were significantly different between the different alleles. Phylogenetic analysis indicated that the three main alleles, AP3, AP8 and AP9, in the cultivars might originate from a common ancestor allele, AP1, in wild rice. CONCLUSIONS: Of these alleles in the cultivars, AP9 was suggested as the best allele in indica, as it has shown strong artificial selection in breeding high-yield rice in the past. It might be valuable to explore the high-yield-related alleles of Gn1a to develop high-yield rice cultivars in future breeding programs.

Cloning a glutathione peroxidase gene from Nelumbo nucifera and enhanced salt tolerance by overexpressing in rice.

A full-length cDNA clone encoding an 866 bp-length glutathione peroxidase protein (NnGPX) was isolated from lotus (Nelumbo nucifera L.). The deduced amino acid sequence of the NnGPX gene had significant homology with ATGPX6. A 3D structural model of the NnGPX was constructed by homology modeling. The cloned NnGPX gene was expressed in Escherichia coli, and a fusion protein of about 40 kDa was detected after isopropyl thiogalactoside induction. Under different concentrations of Na2SeO3 treatments, NnGPX was found to be an enzyme that does not contain selenium. Real-time PCR analysis showed that the NnGPX gene was expressed in all organs of lotus, and its high expression mainly occurred in organs with active metabolisms. NnGPX transcript increased remarkably in response to cold, heat, mechanical damage, and salt treatment. Subsequently, the NnGPX gene was introduced in Oryza sativa cv. Yuetai B. PCR results verified the integration of this gene into the genome of rice and reverse transcription-PCR verified that this gene had been expressed in transgenic rice. The transgenic plants were significantly more tolerant to salt stress compared with the wild-type.

Identification of functional candidate genes for drought tolerance in rice.

Drought tolerance (DT) in rice is known to be controlled by many quantitative trait loci (QTLs) and involved differential expression of large numbers of genes, but linking QTLs with their underlying genes remains the most challenging issue in plant molecular biology. To shed some light on this issue, differential gene expression in response to PEG simulated drought in 3 unique genetic materials (a lowland rice, IR64 and its derived line, PD86 which has 11 introgressed DT QTLs, and a upland rice IRAT109) was investigated using a PCR-based subtractive hybridization strategy. More than 300 unique subtracted cDNA sequences, covering genes of diverse cellular activities and functions, were identified and confirmed by semi-quantitative and quantitative RT-PCR. Detailed bioinformatics analyses of the data revealed two interesting results. First, the levels and mechanisms of DT of the three rice lines were associated with the number and types of differentially expressed genes, suggesting different DT mechanisms in rice are controlled by different sets of genes and different metabolic pathways, and most differentially expressed genes under drought were able to contribute to DT. Second, there appeared a high correspondence in genomic location between DT QTLs and clusters of differentially expressed genes in rice, suggesting some DT QTLs may represent clusters of co-regulated and functionally related genes. Thus, differential gene expression analyses using genetically characterized materials can provide additional insights into the molecular basis of QTLs and convergent evidence to shortlist the candidate genes for target QTLs.