- Dosage compensation
A mechanism for regulating chromosome-wide gene expression based on the ratio of autosomes to sex chromosomes. In C. elegans, the hermaphrodite is XX with two X chromosomes while the male is X0 with only one X chromosome. Dosage compensation machinery in these nematodes reduces expression of genes on both X chromosomes in the hermaphrodite.
- Gene silencing
Inactivation of gene expression can occur at both the level of transcription and post-transcription. All silencing mechanisms are identical in that they require a small RNA species to provide the necessary gene sequence specificity and effector molecules that bind to the RNAs to process the RNA and to direct its inhibitory activity. Studies of these mechanisms in C. elegans has elucidated a number of different RNA-mediated post-transcriptional mechanisms. These mechanisms differ in the species of small RNAs involved. The different classes of small RNAs in C. elegans includes, microRNAs (miRNA), small interfering RNAs (siRNAs or rasi's), X-chromosome cluster RNAs (X-cluster), tiny noncoding RNAs (tncRNAs), and Piwi-associated RNAs (piRNAs). Gene silencing is accepted as a defense mechanism that evolved to protect the host from exogenous (foreign) sequence such as viral and transposon sequence. It has also been shown that gene silencing plays a critical role in endogenous gene expression to control the developmental timing of genes require for cell specificity, as well as playing a role in aging.
- Unfolded protein response - Cytosolic
A change in activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a protein that is not folded in its correct three-dimensional structure.
- Sensory perception
The series of events required for an organism to receive a sensory stimulus, convert it to a molecular signal, and recognize and characterize the signal. This is a neurological process.
- Signal transduction
Signal transduction begins with a stimulating event, such as a ligand binding to a receptor on the surface of the cell, and is followed by intracellular signaling steps that eventually trigger a response. In many cases the end response is modification of the regulation of gene transcription, but could also be the regulation of a metabolic process.
- Thermotaxis
The directed movement of an organism in response to a temperature gradient. Movement may be towards either a higher or lower temperature.
- Hormesis
The process whereby a low exposure to a toxin or stressor produces a generally positive response in the animal that is the opposite effect produced in response to a higher exposure. This can be observed in cases where C. elegans is exposed to short doses of temperature stress during development. Under such limited exposures, animals exhibit a longer life span than animals reared at room temperature. However, extended exposure to thermal stress results in severely shortened lifespans.
- Male sexual development
The establishment of the sex of a male organism by physical and physiological differentiation through sex-specific developmental pathways leading to a fully fertile male of the species.
- Adaptation
Adaptation occurs when a stimulus that once elicited a particular response, now elicits the opposite reaction. In C. elegans, this behavior has been shown through chemotaxis studies where extended exposure to an odor in the absence of food will result in a suppression of the chemotaxis response. In addition, by coupling an attractive stimulus to a starvation environment, the once attractive chemical is responded to as a repellent. However, these adaptations can be restored by brief exposure to the stimulus in the presence of food.