Analysis of behavior using genetical genomics in mice as a model: from alcohol preferences to gene expression differences.

Most familial behavioral phenotypes result from the complex interaction of multiple genes. Studies of such phenotypes involving human subjects are often inconclusive owing to complexity of causation and experimental limitations. Studies of animal models argue for the use of established genetic strains as a powerful tool for genetic dissection of behavioral disorders and have led to the identification of rare genes and genetic mechanisms implicated in such phenotypes. We have used microarrays to study global gene expression in adult brains of four genetic strains of mice (C57BL/6J, DBA/2J, A/J, and BALB/c). Our results demonstrate that different strains show expression differences for a number of genes in the brain, and that closely related strains have similar patterns of gene expression as compared with distantly related strains. In addition, among the 24 000 genes and ESTs on the microarray, 77 showed at least a 1.5-fold increase in the brains of C57BL/6J mice as compared with those of DBA/2J mice. These genes fall into such functional categories as gene regulation, metabolism, cell signaling, neurotransmitter transport, and DNA/RNA binding. The importance of these findings as a novel genetic resource and their use and application in the genetic analysis of complex behavioral phenotypes, susceptibilities, and responses to drugs and chemicals are discussed.     

Application of nanomaterials in three-dimensional stem cell culture

Petri dish cultured cells have for long provided scientists an aperture to understanding cell's behavior both in normal and disease states as well as in vitro and in vivo. But recent advances have brought to light how the architecture and composite nature of the immediate environment within which the cell is proliferated can profoundly influence its phenotypic features and functions, thus making obvious, limitations of the conventional two-dimensional cell culture despite it cost effectiveness. Fortunately, the transition to three-dimensional (3D) cell culture has occurred concurrently with expanded knowledge of nanoscience and materials, thereby lending significant impetus for innovative research. This review is focused on the application of nanoparticles in 3D stem cell breeding, recent trends and developments in medical sciences for improved drug delivery, and treatment approaches to some human diseases. We also reviewed prevailing challenges and concerns of nanotoxicity as it continues to impede and delay clinical applications as well the ongoing concerted and multidisciplinary efforts to overcome them.     

Transcriptomic profiling of maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) seedlings in response to <Emphasis Type="Italic">Pseudomonas putida</Emphasis> stain FBKV2 inoculation under drought stress

Several mechanisms have been proposed for plant growth-promoting rhizobacteria (PGPR)-mediated drought stress tolerance in plants, but little is known about the molecular pathways involved in the drought tolerance promoted by PGPR. We, therefore, aim to study the differential gene response between Pseudomonas putida strain FBKV2 and maize interaction under drought stress using Illumina sequencing. RNA Seq libraries were generated from leaf tissue of maize seedlings with and without strain FBKV2 subjected to drought stress. The libraries were mapped with maize genome database for the identification of differentially expressed genes (DEGs). The expression studies confirmed the downregulation of ethylene biosynthesis (ET), abscisic acid (ABA) and auxin signaling, superoxide dismutase, catalase, and peroxidase in FBKV2-inoculated seedlings. On the other hand, genes involved in β-alanine and choline biosynthesis, heat shock proteins, and late embryogenesis abundant (LEA) proteins were upregulated, which could act as key elements in the drought tolerance conferred by P. putida strain FBKV2. Another remarkable expression was observed in genes encoding benzoxazinoid (BX) biosynthesis which act as the chemoattractant, which was further confirmed by gfp-labeled P. putida strain FBKV2 root colonization studies. Overall, these results indicate that secretion of BXs attracted P. putida strain FBKV2 resulted in root colonization and mediated drought tolerance by modulating metabolic, signaling, and stress-responsive genes.     

Cyclophosphamide-Induced IN VIVO Sister Chromatid Exchanges (Sce) in MUS MUSCULUS. III. Quantitative Genetic Analysis

In vivo cyclophosphamide (CP)-induced sister chromatid exchanges (SCEs) were evaluated in females from five genetic strains of mice (C57BL/6J, C3H/S, 129/ReJ, BALB/c and DBA/2) and their F₁ hybrids. Baseline (noninduced) SCE values differ significantly among strains, 129/ReJ having the lowest and DBA/2 having the highest mean SCE per cell values. In general, the baseline SCE of a given F₁ is within the range of its corresponding parental strains or near the lower parental value. Furthermore, there is a genotype-dependent increase in mean SCEs per cell with CP dose. Strain differences in SCE induction are noted particularly at the two higher CP doses (4.50 and 45.0 mg/kg). In general, F₁ hybrids involving a strain with high induced SCEs and a strain with low induced SCEs exhibit mean SCE values that are closer to the value of the lower strain. F₁ s involving two strains with high SCEs or two strains with low SCEs yield SCEs not different from parental strains. The method of diallel cross analysis showed the order of dominance of these strains in SCE induction to be 129/ReJ BALB/c C3H/S DBA/2 C57BL/6J. These results support the involvement of predominantly nonadditive genetic factors as major gene(s) in SCE induction. In addition, involvement of random and independent events in SCE induction is suggested by the distribution of SCEs which follows a Poisson distribution.     

Lipid changes after leaf wounding in Arabidopsis thaliana: expanded lipidomic data form the basis for lipid co‐occurrence analysis

A direct‐infusion electrospray ionization triple–quadrupole mass spectrometry method with multiple reaction monitoring (MRM) was employed to measure 264 lipid analytes extracted from leaves of Arabidopsis thaliana subjected to mechanical wounding. The method provided precise measurements with an average coefficient of variation of 6.1%. Lipid classes analyzed comprised galactolipids and phospholipids (including monoacyl molecular species, molecular species with oxidized acyl chains, phosphatidic acids (PAs)), tri‐ and tetra‐galactosyldiacylglycerols (TrGDGs and TeGDGs), head‐group‐acylated galactolipids, and head‐group‐acylated phosphatidylglycerol (acPG), sulfoquinovosyldiacylglycerols (SQDGs), sphingolipids, di‐ and tri‐acylglycerols (DAGs and TAGs), and sterol derivatives. Of the 264 lipid analytes, 254 changed significantly in response to wounding. In general, levels of structural lipids decreased, whereas monoacyl molecular species, galactolipids and phosphatidylglycerols (PGs) with oxidized fatty acyl chains, PAs, TrGDGs, TeGDGs, TAGs, head‐group‐acylated galactolipids, acPG, and some sterol derivatives increased, many transiently. The observed changes are consistent with activation of lipid oxidizing, hydrolyzing, glycosylating, and acylating activities in the wounding response. Correlation analysis of the levels of lipid analytes across individual control and treated plants was used to construct a lipid dendrogram and to define clusters and sub‐clusters of lipid analytes, each composed of a group of lipids which occurred in a coordinated manner. Current knowledge of metabolism supports the notion that observed sub‐clusters comprise lipids generated by a common enzyme and/or metabolically downstream of a common enzyme. This work demonstrates that co‐occurrence analysis, based on correlation of lipid levels among plants, is a powerful approach to defining lipids generated in vivo by a common enzymatic pathway.