Development Of Compound Eye Research Articles

The beginning of pattern formation in theDrosophilacompound eye: the morphogenetic furrow and the second mitotic wave

Events in the morphogenetic furrow set the stage for all subsequent compound eye development in Drosophila. The periodic pattern of the adult eye begins in the furrow with the spaced initiation of ommatidial rudiments, the preclusters. A wave of mitosis closely follows the furrow. A cell-by-cell analysis reveals details of these events. Early stages of ommatidial assembly can be resolved using a lead sulfide stain. Overt ommatidial organization begins in the morphogenetic furrow as cells gather into periodically spaced concentric aggregates. A stereotyped sequence of cell rearrangements converts these aggregates into preclusters. In the furrow, new rows of ommatidia are initiated at the equator and grow as new clusters are added to the peripheral ends. Mitotic labeling using BrdU feeds shows that all cells not incorporated into a precluster divide. BrdU injections show that cells divide roughly simultaneously between two adjacent rows of ommatidia.

A Dubious Case for Somatic Mutation Generating Unstable Morphological Variations of Compound Eyes of Drosophila melanogaster.

The eyeless Nanjo is a mutation that was found in a natural population of Drosophila melanogaster. Genetic analysis of this mutant revealed the following characteristics of this mutation. (1) The homozygous eyelessness is caused by a single recessive mutation which prevents the normal development of compound eyes. (2) An extremely variable morphological eye phenotype was generated by the introduction of a different genetic background to this mutant. (3) The estimated germ line reversion rate was very high. These results suggest that an extremely variable morphological eye phenotype might result from spontaneous somatic excision of some kind of a transposable element.

A novel intercellular junction between cone cells in the compound eye of Ephestia kuehniella.

A previously unidentified intercellular junction between cone cells in the compound eye of the moth Ephestia is described. The junctions are characterized by deposition of granular material, in register, along portions of the membranes of adjacent cone cells during compound eye development and by a constant intercellular space of 8-10 nm. Accumulation of the cone cell material along localized regions of the cell membrane suggests an interaction between a specialized area of the membrane and a specific cytoplasmic constituent, and the exact matching of the regions of deposition between adjacent cells implies intercellular interaction. The junctional nature of these membrane regions is often obscured in the adult crystalline cone but is inferred from observations on developing cone cells.

Genes in subdivision IB of the Drosophila melanogaster X-chromosome and their influence on neural development

Genes within subdivision 1B of the X-chromosome of Drosophila melanogaster are known to affect the development of both the central (CNS) and the peripheral (PNS) embryonic nervous system. In this paper we describe the phenotypes of embryos hemizygous for terminal and interstitial deletions of region 1B1-1B10, and of embryos carrying different mutations in certain genes of this region. A minimum of 6 genetic functions that are involved in neural development can be defined in this region. Three of these genes, mapping to the l'sc(a gene of the achaete-scute complex, ASC),elav and vnd loci, affect major and apparently different aspects of CNS development. Two additional genes of the ASC, ac and sc alpha, also play a role in CNS development, although their participation can only be demonstrated under certain conditions. Finally, in the rightmost part of the region uncovered by the deletion Df(1)260.1, two not yet well separated functions are found to be required for embryonic CNS and compound eye development, respectively. Of these two functions, the embryonic one is similar to the ones of ac and sc alpha, and can therefore be considered as a new element of the ASC.

The Expression of Neurogenic Loci in Imaginal Epidermal Cells of Drosophila Melanogaster

Six zygotically expressed genomic loci of Drosophila melanogaster, N, bib, mam, neu, Dl and E (spl), have previously been found to be involved in the commitment of ectodermal cells as neuroblasts. We have studied phenotypes induced by various mutant alleles at these 6 loci in imaginal epidermal cells, in order to assess possible implications of the genes in functions other than early neurogenesis. When homozygous, any of these mutations except bib affected the development of bristles and compound eye in various ways. These range from cell death to the production of additional bristles and several defects in ommatidial patterning, depending on the allele used. In contrast clones of bib homozygous cells exhibited wild-type phenotypes. The differences found in the expression of the neurogenic genes are discussed with respect to a hypothesis on the genetic control of neurogenesis.

Postembryonic growth of the compound eye of the cockroach

The postembryonic growth of the compound eye of the cockroach Periplaneta americana involves increases in the size of the individual ommatidia as well as a 35-fold increase in the number of ommatidia. These ommatidia are added to the anterior, dorsal, and ventral margins of the eye by means of an almost continuous process of cell division in the proliferation zone in these margins. This proliferation phase is followed by a process of maturation of bundles of 'pre-ommatidial' cells into mature ommatidia, a process which involves further cell division. Processes involved in compound-eye development are investigated by eye margin grafting, histological techniques and cell proliferation studies.

The eye margin and compound-eye development in the cockroach: evidence against recruitment

The compound eye of the cockroach nymph grows from stadium to stadium by the addition of new ommatidia to the growing edge of the eye. By a series of transplant operations on Periplaneta americana and from SEM studies on Gromphadorhina portentosa it is shown that the proliferating region of the eye margin is a budding zone. There is no recruitment of larval head-capsule epidermis into the eye.

The development of the compound eyes of Penaeus duorarum (Crustacea: Decapoda) with remarks on the nervous system.

The development of the compound eyes and nervous system of the penaeid shrimp,Penaeus duorarum, from the first nauplius to the first postlarva, has been studied. The first anlage of the compound eyes is a pair of optic discs on the front of the animal. These increase in size through cell-division until the second protozoea stage, where the eye-stalks appear with ommatidia and optic neuropiles developed. The original neuroectoderm of the optic discs is retained in the shape of a proliferation zone throughout the life of the animal. From the optic discs, develop the ommatidia, the lamina ganglionaris, and the medulla externa. The medullae interna and terminalis develop from cells coming from the brain anlage. From the second protozoea and onwards, the development is less rapid. The final shape of the adult eye is reached during the postlarval stages and includes the appearance of a few more pigments and a perfecting of several features. A scheme for the development of crustacean compound eyes is laid down. Further, the medulla externa of the Malacostraca and the single medulla of non-malacostracan crustaceans are homologized. The continuous growth of the nervous system is traced in the development of the neuropile. The appearance of glomeruli structures is reported, as are also, to some extent, neurosecretory organs. The development of the SPX-organ conforms to that of other decapods.

The development of the compound eye of Crangon

The development of the compound eye of Crangon