What are imaginal discs in Drosophila?

What is an imaginal disc? An imaginal disc is a sac-like epithelial structure found inside the larva of insects that undergo metamorphosis. Once the larva turns into a pupa, almost all the larval tissues degenerate and the imaginal discs turn into the external structures of the head, thorax, limbs and genitalia.

What are wing discs?

Drosophila imaginal discs are epithelial structures that give rise to the adult body structures. The wing disc contains about 30 cells at the beginning of the first instar larva and reaches at metamorphosis, almost 4 days later, a number of about 50,000 cells (Milan et al., 1996b).

Do Hemimetabolous insects have imaginal discs?

And although the term imaginal disc is used only for holometabolous insects, it is only the invaginated morphology of most discs that distinguishes them from structures like the external wing pads of hemimetabolous insects, which also are morphologically distinct and form adult wings during the final molt.

Who discovered imaginal discs?

Jan Swammerdam
The role of the imaginal disc in insect development was first elucidated by Jan Swammerdam. During the pupal stage, many larval structures are broken down, and adult structures, including the discs, undergo rapid development.

Why are discs called imaginal?

Why are they called imaginal discs? That’s easy… ‘imago’ is a Latin word that means ‘image’ and is used by entomologists to refer to the mature stage of insects. The imaginal discs get their name since they are ‘disc’-shaped structures that will originate the imago.

What does the word imaginal mean?

imagination
Definition of imaginal (Entry 1 of 2) : of or relating to imagination, images, or imagery. imaginal. adjective (2)

Where do imaginal cells come from?

Imaginal disks are epithelial structures characteristic of insects that undergo complete metamorphosis. These epithelia originate during embryonic development from groups of ectodermal cells that grow during the larval stages to form the mature disk.

What is imaginal cell?

Imaginal cells are tissue-specific progenitors allocated in embryogenesis that remain quiescent during embryonic and larval life. During Drosophila metamorphosis, most larval cells die. Pupal and adult tissues form from imaginal cells.

How many imaginal discs are there?

19 discs
The imaginal discs get their name since they are ‘disc’-shaped structures that will originate the imago. How many imaginal discs does a fly have? There are 19 discs in total: the epidermis of the head, thorax and limbs of the fly come from 9 bilateral pairs of discs and the genitalia come from a medial disc.

How are imaginal discs dissected from third-instar larvae?

Imaginal discs (eye-antennal discs or wing discs) with genetically manipulated somatic clones (labeled with fluorescent proteins) are dissected out from third-instar larvae in phosphate-buffered saline (PBS) and are set on the prepared chambers as follows: 1. Dissect larvae in PBS and take imaginal discs out from the larvae using forceps. 2.

How do Drosophila melanogaster larvae regenerate wing imaginal discs?

In wing imaginal discs of Drosophila melanogaster larvae, dying cells release mitogenic signals ( Grusche et al., 2011; Ryoo et al., 2004; Sun and Irvine, 2011 ). The resulting proliferation of the neighbors compensates for cell loss and helps regenerate the disc.

What is the anatomy of the leg imaginal disc?

The leg imaginal disc, like the wing disc, is divided into anterior/posterior (A/P) and dorsal/ventral (D/V) compartments. In the leg disc, Hedgehog (Hh), secreted from posterior cells, induces dpp predominantly dorsally and wingless ( wg) ventrally in the anterior compartment ( Fig. 1 E).