Project description:Stressors may have negative or positive effects in dependence of the dose (hormesis). We studied this phenomenon in Caenorhabditis elegans by applying weak or severe abiotic (cadmium, CdCl2) and/or biotic stress (different bacterial diets) during cultivation/breeding of the worms, and determining developmental speed or survival rates and performing transcriptome profiling and RT-qPCR analyses to explore the genetic basis of the detected phenotypic differences. This study showed that a bacterial diet resulting in higher levels of energy resources in the worms (E. coli OP50 feeding) or weak abiotic and biotic stress especially promote the resistance against severe abiotic or biotic stress and the age-specific survival rate of WT.
Project description:Gills of teleost fish represent a vital multifunctional organ; however, they are subjected to environmental stressors, causing gill damage. Gill damage is associated with significant losses in the Atlantic salmon aquaculture industry. Gill disorders due to environmental stressors are exacerbated by global environmental changes, especially with open-net pen aquaculture (as farmed fish lack the ability to escape those events). The local and systemic response to gill damage, concurrent with several environmental insults, are not well investigated. We performed field sampling to collect gill and liver tissue after several environmental insults. Using a 44K salmonid microarray platform, we aimed to compare the transcriptomes of pristine and moderately damaged gill tissue. The gill damage-associated biomarker genes and associated qPCR assays arising from this study will be valuable in future research aimed at developing therapeutic diets to improve farmed salmon gill health.
Project description:Escherichia coli spans a genetic continuum from enteric strains to several phylogenetically distinct, atypical lineages that are rare in humans, but more common in extra-intestinal environments. To investigate the link between gene regulation, phylogeny and diversification in this species, we analyzed global gene expression profiles of four strains representing distinct evolutionary lineages, including a well-studied laboratory strain, a typical commensal (enteric) strain and two environmental strains. RNA-Seq was employed to compare the whole transcriptomes of strains grown under batch, chemostat and starvation conditions. Highly differentially expressed genes showed a significantly lower nucleotide sequence identity compared with other genes, indicating that gene regulation and coding sequence conservation are directly connected. Overall, distances between the strains based on gene expression profiles were largely dependent on the culture condition and did not reflect phylogenetic relatedness. Expression differences of commonly shared genes (all four strains) and E. coli core genes were consistently smaller between strains characterized by more similar primary habitats. For instance, environmental strains exhibited increased expression of stress defense genes under carbon-limited growth and entered a more pronounced survival-like phenotype during starvation compared with other strains, which stayed more alert for substrate scavenging and catabolism during no-growth conditions. Since those environmental strains show similar genetic distance to each other and to the other two strains, these findings cannot be simply attributed to genetic relatedness but suggest physiological adaptations. Our study provides new insights into ecologically relevant gene-expression and underscores the role of (differential) gene regulation for the diversification of the model bacterial species. Four E.coli strains, laboratory strain K12 (MG1655), a commensal model strain (IAI1), a soil-isolated strain (TW11588-Clade IV), and a freshwater-isolated strain (TW09308âClade V) were used. Each strain was grown on a minimal growth medium (Ihssen and Egli, 2004) in three treatment modes: chemostat, batch, and starvation. Cells from batch culture were collected when reaching steady-state. For starvation, the medium flow was stopped during steady-state and bacteria were collected after 4âh.
Project description:In response of the germplasm resources conservation in China, the characters of a superior land-race of broad bean (Vicia faba L.) Cixidabaican (CX) were identified compared with Lixiyicun (LX) introduced from Japan.