A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 

Glossary - Q





Q cell

Q1, Q2 (formerly)

A pair of lateral neuroblasts that migrate separately within the body cavity during larval stages to produce a variety of cell types. See description in Hedgecock et al., 1990.


A temporary cessation of movement. A brief quietus has been noted at the beginning of mating behavior, once the male tail has encountered the hermaphrodite vulva, at which time the hermaphrodite (or female) stops moving (Barker, 1994). A more prolonged quietus, termed the “lethargus”, overcomes the animal at the onset of each molt (Cassada and Russell, 1975). Similarly, dauer animals and well fed adults often display prolonged periods of quietus.

See Lethargus


1) A gradual slowing down of metabolism and movement possibly leading to complete paralysis, if unfavorable environmental conditions such as a drop in temperature, a lowering of oxygen levels, or desiccation, persist.

2) Developmental or environmental signals may induce a paused or arrested phase of the cell cycle (G0).

3) The primordial germ cells (Z2 and Z3) and the somatic gonad precursor cells (Z1 and Z4) remain in a state of mitotic quiescence until after the embryo hatches.

See Anoxia
See Cryptobiosis
See Lethargus
See Dauer
See Diapause
See Molt
See Quietus

Quorum sensing  

A mode of behavior in which groups of cells (or animals) coordinate their activity based upon intercellular signaling to determine their relative numbers. The process is noted most often in virulent bacteria, who may coordinate their rate of cell division, their tendency to form biofilms or their secretion of products to achieve maximum effect. Pathogenic bacteria use quorum sensing in coordinated attacks on C. elegans (Tan et al., 1999). Studies in Pseudomonas aeruginosa have identified a genetically controlled signaling cascade that regulates this process (Juhas et al., 2004).

Edited for the web by Laura A. Herndon. Last revision: November 15, 2013. This section should be cited as: Herndon, L.A. and Hall, D.H. 2010. Glossary Q. In WormAtlas.  doi:10.3908/wormatlas.6.17