Formation of spermatophore in ejaculatory duct of yellow mealworm beetle, Tenebrio molitor: SEM study

Author(s):  
Frantíšek Weyda ◽  
George M. Happ

Main role of the accessory glands of Tenebrio molitor male is to facilitate transfer of sperm to the females. They produce heterogeneous secretions. Two anatomically distinct glands are present. While the tubular accessory glands (TAG) are composed of the secretory cells of one type only, the bean-shaped accessory glands (BAG) consist of eight cellular types. Low viscosity secretion of the TAG mix with sperms forming seminal fluid while high viscosity secretions (spermatophorins) of the BAG are largely transformed into the insoluble wall and core of the spermatophore. The prespermatophoric mass is transferred to the ejaculatory duct (EJD) where solidify and forms the complex spermatophore. Immunocytochemical experiments with monoclonal antibodies based on the colloidal gold technique were used in order to understand exact composition of individual layers of the spermatophore. In the recent study we have used SEM to observe the whole process of the formation of spermatophore in the ejaculatory duct.

Author(s):  
S. Bricker ◽  
G. M. Happ

The male mealworm, Tenebrio molitor produces a spermatophore to facilitate transfer of sperm to the female. The wall of the spermatophore is largely produced from the secretions of the paired bean-shaped accessory glands (BAGs). As the cottony pre-spermatophoric mass from the BAGs comes together in the ejaculatory duct where it is molded into the spermatophore, it becomes tougher and more elastic. The mechanisms involved in this stabilization of the wall of the spermatophore were unknown. Mechanisms of stabilization of other acellular structures assembled in extracellular space include quinone-tanning and β-sclerotization in cuticle, shear forces in silk, and pH changes in the spermatophore of Rhodnius. The cells found in the epithelium of the upper ejaculatory duct of the mealworm beetle were examined by transmission electron microscopy for ultrastructural evidence of a role in the stabilization of the spermatophore wall.


2018 ◽  
Author(s):  
E. Prince ◽  
M. Brankatschk ◽  
B. Kroeger ◽  
D. Gligorov ◽  
C. Wilson ◽  
...  

AbstractIt is known that the male seminal fluid contains factors that affect female post-mating behavior and physiology. In Drosophila, most of these factors are secreted by the two epithelial cell types that make up the male accessory gland: the main and secondary cells. Although secondary cells represent only 4% of the cells of the accessory gland, their contribution to the male seminal fluid is essential for sustaining the female post-mating response. To better understand the function of the secondary cells, here we investigate their molecular organization, particularly with respect to the intracellular membrane transport machinery. We determined that large vacuole-like structures found in the secondary cells are trafficking hubs labeled by Rab6, 7, 11 and 19. Furthermore, these cell-specific organelles are essential for the long-term post-mating behavior of females and that their formation is directly dependent upon Rab6. Our discovery adds to our understanding of Rab proteins function in secretory cells. We have created an online, open-access imaging resource as a valuable tool for the intracellular membrane and protein traffic community.


1976 ◽  
Vol 54 (6) ◽  
pp. 990-1002 ◽  
Author(s):  
G. H. Gerber

The histogenic changes in the internal genitalia and mesenteron and the hardening and darkening of the cuticle during the first days of adult life in Tenebrio molitor L. are described. At emergence, the testes contain mature spermatozoa and the ovaries possess small oocytes. During the first 3 days, the shape, size, appearance, and staining characteristics of the secretory cells of the lateral oviducts, female accessory gland, tube accessory glands, bean-shaped accessory glands, and glandular region of the vasa deferentia change. Similar changes were not seen in the seminal vesicles and spermatheca. All of the secondary sex glands are filled with secretion by day 4. In the midgut, changes occur in the size, shape, and appearance of the epithelial cells by the 3rd day, and a peritrophic membrane is secreted during days 2 and 3. Most adults do not begin to feed until after the 3rd day. By day 3, the hardening and darkening of the cuticle are completed. All of these changes clearly are associated with adult maturation, especially sexual maturation, and most or all of the them must take place before the adults are able to copulate and oviposit.


2019 ◽  
Vol 116 (49) ◽  
pp. 24719-24728 ◽  
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Sarah Bonham ◽  
Thomas Miller ◽  
Philip D. Charles ◽  
...  

Seminal fluid proteins (SFPs) exert potent effects on male and female fitness. Rapidly evolving and molecularly diverse, they derive from multiple male secretory cells and tissues. In Drosophila melanogaster, most SFPs are produced in the accessory glands, which are composed of ∼1,000 fertility-enhancing “main cells” and ∼40 more functionally cryptic “secondary cells.” Inhibition of bone morphogenetic protein (BMP) signaling in secondary cells suppresses secretion, leading to a unique uncoupling of normal female postmating responses to the ejaculate: refractoriness stimulation is impaired, but offspring production is not. Secondary-cell secretions might therefore make highly specific contributions to the seminal proteome and ejaculate function; alternatively, they might regulate more global—but hitherto undiscovered—SFP functions and proteome composition. Here, we present data that support the latter model. We show that in addition to previously reported phenotypes, secondary-cell-specific BMP signaling inhibition compromises sperm storage and increases female sperm use efficiency. It also impacts second male sperm, tending to slow entry into storage and delay ejection. First male paternity is enhanced, which suggests a constraint on ejaculate evolution whereby high female refractoriness and sperm competitiveness are mutually exclusive. Using quantitative proteomics, we reveal changes to the seminal proteome that surprisingly encompass alterations to main-cell–derived proteins, indicating important cross-talk between classes of SFP-secreting cells. Our results demonstrate that ejaculate composition and function emerge from the integrated action of multiple secretory cell types, suggesting that modification to the cellular make-up of seminal-fluid-producing tissues is an important factor in ejaculate evolution.


2019 ◽  
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Sarah Bonham ◽  
Thomas Miller ◽  
Philip D. Charles ◽  
...  

ABSTRACTSeminal fluid proteins (SFPs) exert potent effects on male and female fitness. Rapidly evolving and molecularly diverse, they derive from multiple male secretory cells and tissues. In Drosophila melanogaster, most SFPs are produced in the accessory glands, which are composed of ∼1000 fertility-enhancing ‘main cells’ and ∼40, more functionally cryptic, ‘secondary cells’. Inhibition of BMP-signalling in secondary cells suppresses secretion, leading to a unique uncoupling of normal female post-mating responses to the ejaculate: refractoriness stimulation is impaired, but offspring production is not. Secondary cell secretions might therefore make a highly specific contribution to the seminal proteome and ejaculate function; alternatively, they might regulate more global – but hitherto-undiscovered – SFP functions and proteome composition. Here, we present data that supports the latter model. We show that in addition to previously reported phenotypes, secondary cell-specific BMP-signalling inhibition compromises sperm storage and increases female sperm use efficiency. It also impacts second male sperm, tending to slow entry into storage and delay ejection. First male paternity is enhanced, which suggests a novel constraint on ejaculate evolution whereby high female refractoriness and sperm competitiveness are mutually exclusive. Using quantitative proteomics, we reveal a mix of specific and widespread changes to the seminal proteome that surprisingly encompass alterations to main cell-derived proteins, indicating important cross-talk between classes of SFP-secreting cells. Our results demonstrate that ejaculate composition and function emerge from the integrated action of multiple secretory cell-types suggesting that modification to the cellular make-up of seminal fluid-producing tissues is an important factor in ejaculate evolution.


1992 ◽  
Vol 288 (1) ◽  
pp. 19-22 ◽  
Author(s):  
M Takiguchi ◽  
T Niimi ◽  
Z H Su ◽  
T Yaginuma

A cDNA of alpha alpha-trehalase (EC 3.2.1.28) from a cDNA library of male bean-shaped accessory gland of the mealworm beetle, Tenebrio molitor, has been isolated by the homology screening approach. Sequence analysis of the cDNA (1830 bp) revealed that the cDNA encoded a protein of 555 amino acids with a calculated M(r) of 64457. The deduced amino acid sequence had significant similarities to rabbit small intestine and Escherichia coli trehalases. Northern blotting and semi-quantitative PCR analyses revealed that a trehalase transcript with about 2.0 kb was abundant in bean-shaped accessory glands. In the glands, the amount of trehalase transcript increased from 1 to 2 days after adult ecdysis. These tissue- and stage-specific gene expressions of trehalase corresponded to the tissue- and stage-specificity of trehalase activity.


2021 ◽  
Vol 120 ◽  
pp. 104065
Author(s):  
A. Urbański ◽  
N. Konopińska ◽  
J. Lubawy ◽  
K. Walkowiak-Nowicka ◽  
P. Marciniak ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document