Synthesis, in vitro and in vivo biological evaluation of novel graveolinine derivatives as potential anti-Alzheimer agents.

A novel series of graveolinine derivatives were synthesized and evaluated as potential anti-Alzheimer agents. Compound 5f exhibited the best inhibitory activity for acetylcholinesterase (AChE) and had surprisingly potent inhibitory activity for butyrylcholinesterase (BuChE), with IC50 values of 0.72 µM and 0.16 µM, respectively. The results from Lineweaver-Burk plot and molecular modeling study indicated non-competitive inhibition of AChE by compound 5f. In addition, these derivatives showed potent self-induced ß-amyloid (Aß) aggregation inhibition. Moreover, 5f didn't show obvious toxicity against PC12 and HepG2 cells at 50 µM. Finally, in vivo studies confirmed that 5f significantly ameliorates the cognitive performances of scopolamine-treated ICR mice. Therefore, these graveolinine derivatives should be thoroughly and systematically studied for the treatment of Alzheimer's disease.

BplMYB46 from Betula platyphylla Can Form Homodimers and Heterodimers and Is Involved in Salt and Osmotic Stresses.

MYB proteins play important roles in the regulation of plant growth, development, and stress responses. Overexpression of BplMYB46 from Betula platyphylla improved plant salt and osmotic tolerances. In the present study, the interaction of eight avian myeloblastosis viral oncogene homolog (MYB) transcription factors with BplMYB46 was investigated using the yeast two-hybrid system, which showed that BplMYB46 could form homodimers and heterodimers with BplMYB6, BplMYB8, BplMYB11, BplMYB12, and BplMYB13. Relative beta-glucuronidase activity and chromatin immunoprecipitation assays showed that the interaction between BplMYB46 and the five MYBs increased the binding of BplMYB46 to the MYBCORE motif. A subcellular localization study showed that these MYBs were all located in the nucleus. Real-time fluorescence quantitative PCR results indicated that the expressions of BplMYB46 and the five MYB genes could be induced by salt and osmotic stress, and the BplMYB46 and BplMYB13 exhibited the most similar expression patterns. BplMYB46 and BplMYB13 co-overexpression in tobacco using transient transformation technology improved tobacco's tolerance to salt and osmotic stresses compared with overexpressing BplMYB13 or BplMYB46 alone. Taken together, these results demonstrated that BplMYB46 could interact with five other MYBs to form heterodimers that activate the transcription of target genes via an enhanced binding ability to the MYBCORE motif to mediate reactive oxygen species scavenging in response to salt and osmotic stresses.

Investigation of single nucleotide polymorphisms based on the intronic sequences of the propylene alcohol dehydrogenase gene in Chinese tobacco genotypes.

A pair of primers was designed to amplify the propylene alcohol dehydrogenase gene sequence based on the cDNA sequence of the tobacco allyl-alcohol dehydrogenase gene. All introns were sequenced using traditional polymerase chain reaction (PCR) methods and T-A cloning. The sequences from common tobacco (Nicotiana tabaccum L.) and rustica tobacco (Nicotiana rustica L.) were analysed between the third intron and the fourth intron of the propylene alcohol dehydrogenase gene. The results showed that the alcohol dehydrogenase gene is a low-copy nuclear gene. The intron sequences have a combination of single nucleotide polymorphisms and length polymorphisms between common tobacco and rustica tobacco, which are suitable to identify the different germplasms. Furthermore, there are some single nucleotide polymorphism sites in the target sequence within common tobacco that can be used to distinguish intraspecific varieties.

Synthesis and biological evaluation of genistein-O-alkylamine derivatives as potential multifunctional anti-Alzheimer agents.

A series of genistein derivatives were synthesized and evaluated as multifunctional anti-Alzheimer agents. The results showed that these derivatives had significant acetylcholinesterase (AChE) inhibitory activity; compound 5a exhibited the strongest inhibition to AChE with an IC50 value (0.034 µM) much lower than that of rivastigmine (6.53 µM). A Lineweaver-Burk plot and molecular modeling study showed that compound 5a targeted both the catalytic active site and the peripheral anionic site of AChE. These compounds also showed potent peroxy scavenging activity and metal-chelating ability. The compounds did not show obvious effect on HepG2 and PC12 cell viability at the concentration of 100 µM. Therefore, these genistein derivatives can be utilized as multifunctional agents for the treatment of AD.

[Application of DNA-related techniques in avian molecular phylogeny].

The DNA techniques most commonly used in avian molecular phylogeny include DNA hybridization, RFLP and DNA sequence analysis, among which DNA sequence analysis is supposed to be the most effective and reliable. DNA hybridization techniques have been widely used in aves, based on which a new avian classification system was born. In avian RFLP analyses, mtDNA are widely used as target sequences. Mitochondrial DNA genes are the most frequently used in avian molecular phylogeny. Although mtDNA phylogenies are likely to be correct in many cases, use of mtDNA sequences can be problematic with such constraints as unilateral inheritance, multiple substitutions, saturations at the third-coded sites, strong bias in base composition and probable nuclear pseudogenes of mtDNA sequences. Although bias are still on the mtDNA sequences, more and more authors turn to nuclear DNA sequences and prefer to a combination of mtDNA and nuclear DNA sequences. And single-copy nuclear DNA receives the most favor. scnDNA introns can perform well in recovering relationships among intermediate to even distantly related congeneric species. scnDNA exons can be used in avian higher ranks. With the exception of molecular markers' own problems including variable rates of nucleotide site evolution, gene hybridization, gene horizontal transfer and lineage sorting, avian molecular phylogeny also faces methodological problems, such as molecular markers selection, taxon sampling and data processing. More attention should be paid to the standardization of methods, not to the new molecular markers.

[Research progress on molecular ecology of Sciurus vulgaris].

Today, the main threats for Sciurus vulgaris are illegal hunting, deforestation, and subsequent population fragmentation, combined with interspecific competition from S. carolinensis in some regions of Europe, which has led to a sharp reduction in the number of population. S. vulgaris has been listed as Near Threatened IUCN Red List and included in key protected wild animals in Jilin Province, China. The molecular ecology of S. vulgaris is developing rapidly with the rapid development of molecular biology methods. In particular, the research of mtDNA fragments and the application squirrel study microsatellite loci has further promoted the molecular ecology of S. vulgaris. In this study, the molecular phylogeny, the genetic diversity and the molecular phylogeography involving the molecular ecology of S. vulgaris were reviewed. Four areas for the future development in molecular ecology of S. vulgaris were proposed: 1) to further explore the molecular phylogeny relationship between S. vulgaris and S. lis; 2) the comparative analysis of the genetic diversity of S. vulgaris for continuous populations, isolated populations and metapopulation; 3) the analysis of molecular phylogeography of S. vulgaris based on other markers of nuclear; 4) to explore whether there existed the quaternary glacial refuge in Asia.