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Insights into the dynamics of hind leg development in honey bee (Apis mellifera L.) queen and worker larvae - A morphology/differential gene expression analysis.

Santos CG, Hartfelder K - Genet. Mol. Biol. (2015)

Bottom Line: By means of histological sections and cell proliferation analysis we followed the developmental dynamics of the hind legs of queens and workers in the fourth and fifth larval instars.In parallel, we generated subtractive cDNA libraries for hind leg discs of queen and worker larvae by means of a Representational Difference Analysis (RDA).From the total of 135 unique sequences we selected 19 for RT-qPCR analysis, where six of these were confirmed as differing significantly in their expression between the two castes in the larval spinning stage.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

ABSTRACT
Phenotypic plasticity is a hallmark of the caste systems of social insects, expressed in their life history and morphological traits. These are best studied in bees. In their co-evolution with angiosperm plants, the females of corbiculate bees have acquired a specialized structure on their hind legs for collecting pollen. In the highly eusocial bees (Apini and Meliponini), this structure is however only present in workers and absent in queens. By means of histological sections and cell proliferation analysis we followed the developmental dynamics of the hind legs of queens and workers in the fourth and fifth larval instars. In parallel, we generated subtractive cDNA libraries for hind leg discs of queen and worker larvae by means of a Representational Difference Analysis (RDA). From the total of 135 unique sequences we selected 19 for RT-qPCR analysis, where six of these were confirmed as differing significantly in their expression between the two castes in the larval spinning stage. The development of complex structures such as the bees' hind legs, requires diverse patterning mechanisms and signaling modules, as indicated by the set of differentially expressed genes related with cell adhesion and signaling pathways.

No MeSH data available.


Related in: MedlinePlus

Hind leg imaginal discs development in honey bee larvae. (A–B) In the fourth larval instar (L4,) the disc occupies the peripodial sac (PS and arrow in A). Mesenchymal cells (MC) are observed inside the disc, which is covered by the larval cuticle (C). (C–E) During the feeding stage of the fifth instar (L5F) the discs grow considerably and the leg compartments start to become apparent, but the epithelium (E) remains unchanged. Muscles cells (M) are adjacent to the epithelium where they will establish future connections. (F) In the legs of early spinning stage (L5S) larva, segmentation is more apparent, but the epithelium still remains the same. A, B - L4 queen; C - L5F1 worker; D - L5F2 worker; E - L5F3 worker; F, L5S1 queen.; C, cuticle; E, epidermis; FB, fat body; MC, mesenchymal cells; M, muscle; PS, peripodial sac; Tr, trachea; TG, thoracic ganglion. Scale bars: A, C, D, E, 100 μm; B, 50 μm; F, 200 μm.
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f01: Hind leg imaginal discs development in honey bee larvae. (A–B) In the fourth larval instar (L4,) the disc occupies the peripodial sac (PS and arrow in A). Mesenchymal cells (MC) are observed inside the disc, which is covered by the larval cuticle (C). (C–E) During the feeding stage of the fifth instar (L5F) the discs grow considerably and the leg compartments start to become apparent, but the epithelium (E) remains unchanged. Muscles cells (M) are adjacent to the epithelium where they will establish future connections. (F) In the legs of early spinning stage (L5S) larva, segmentation is more apparent, but the epithelium still remains the same. A, B - L4 queen; C - L5F1 worker; D - L5F2 worker; E - L5F3 worker; F, L5S1 queen.; C, cuticle; E, epidermis; FB, fat body; MC, mesenchymal cells; M, muscle; PS, peripodial sac; Tr, trachea; TG, thoracic ganglion. Scale bars: A, C, D, E, 100 μm; B, 50 μm; F, 200 μm.

Mentions: The legs of honey bees develop from imaginal discs. Sitting in the ventral midline of the larval body they are contiguous with the body wall epidermis, representing pockets of thickened epidermis beneath the ventral thoracic cuticle (Figure 1B,C,F). We analyzed leg disc development in queens and workers from the fourth instar larvae (L4) until the prepupal stage (L5PP) and all subsequent descriptions equally suit both castes, as there were no obvious histological differences between the two.


Insights into the dynamics of hind leg development in honey bee (Apis mellifera L.) queen and worker larvae - A morphology/differential gene expression analysis.

Santos CG, Hartfelder K - Genet. Mol. Biol. (2015)

Hind leg imaginal discs development in honey bee larvae. (A–B) In the fourth larval instar (L4,) the disc occupies the peripodial sac (PS and arrow in A). Mesenchymal cells (MC) are observed inside the disc, which is covered by the larval cuticle (C). (C–E) During the feeding stage of the fifth instar (L5F) the discs grow considerably and the leg compartments start to become apparent, but the epithelium (E) remains unchanged. Muscles cells (M) are adjacent to the epithelium where they will establish future connections. (F) In the legs of early spinning stage (L5S) larva, segmentation is more apparent, but the epithelium still remains the same. A, B - L4 queen; C - L5F1 worker; D - L5F2 worker; E - L5F3 worker; F, L5S1 queen.; C, cuticle; E, epidermis; FB, fat body; MC, mesenchymal cells; M, muscle; PS, peripodial sac; Tr, trachea; TG, thoracic ganglion. Scale bars: A, C, D, E, 100 μm; B, 50 μm; F, 200 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4612609&req=5

f01: Hind leg imaginal discs development in honey bee larvae. (A–B) In the fourth larval instar (L4,) the disc occupies the peripodial sac (PS and arrow in A). Mesenchymal cells (MC) are observed inside the disc, which is covered by the larval cuticle (C). (C–E) During the feeding stage of the fifth instar (L5F) the discs grow considerably and the leg compartments start to become apparent, but the epithelium (E) remains unchanged. Muscles cells (M) are adjacent to the epithelium where they will establish future connections. (F) In the legs of early spinning stage (L5S) larva, segmentation is more apparent, but the epithelium still remains the same. A, B - L4 queen; C - L5F1 worker; D - L5F2 worker; E - L5F3 worker; F, L5S1 queen.; C, cuticle; E, epidermis; FB, fat body; MC, mesenchymal cells; M, muscle; PS, peripodial sac; Tr, trachea; TG, thoracic ganglion. Scale bars: A, C, D, E, 100 μm; B, 50 μm; F, 200 μm.
Mentions: The legs of honey bees develop from imaginal discs. Sitting in the ventral midline of the larval body they are contiguous with the body wall epidermis, representing pockets of thickened epidermis beneath the ventral thoracic cuticle (Figure 1B,C,F). We analyzed leg disc development in queens and workers from the fourth instar larvae (L4) until the prepupal stage (L5PP) and all subsequent descriptions equally suit both castes, as there were no obvious histological differences between the two.

Bottom Line: By means of histological sections and cell proliferation analysis we followed the developmental dynamics of the hind legs of queens and workers in the fourth and fifth larval instars.In parallel, we generated subtractive cDNA libraries for hind leg discs of queen and worker larvae by means of a Representational Difference Analysis (RDA).From the total of 135 unique sequences we selected 19 for RT-qPCR analysis, where six of these were confirmed as differing significantly in their expression between the two castes in the larval spinning stage.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil.

ABSTRACT
Phenotypic plasticity is a hallmark of the caste systems of social insects, expressed in their life history and morphological traits. These are best studied in bees. In their co-evolution with angiosperm plants, the females of corbiculate bees have acquired a specialized structure on their hind legs for collecting pollen. In the highly eusocial bees (Apini and Meliponini), this structure is however only present in workers and absent in queens. By means of histological sections and cell proliferation analysis we followed the developmental dynamics of the hind legs of queens and workers in the fourth and fifth larval instars. In parallel, we generated subtractive cDNA libraries for hind leg discs of queen and worker larvae by means of a Representational Difference Analysis (RDA). From the total of 135 unique sequences we selected 19 for RT-qPCR analysis, where six of these were confirmed as differing significantly in their expression between the two castes in the larval spinning stage. The development of complex structures such as the bees' hind legs, requires diverse patterning mechanisms and signaling modules, as indicated by the set of differentially expressed genes related with cell adhesion and signaling pathways.

No MeSH data available.


Related in: MedlinePlus