scholarly journals Atypical septate junctions maintain the somatic enclosure around maturing spermatids and prevent premature sperm release in Drosophila testis

Biology Open ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. bio036939 ◽  
Author(s):  
Pankaj Dubey ◽  
Tushna Kapoor ◽  
Samir Gupta ◽  
Seema Shirolikar ◽  
Krishanu Ray
Keyword(s):  
Septate Junctions ◽  
Sperm Release ◽  
Drosophila Testis

scholarly journals Time-lapse imaging of Drosophila testis for monitoring actin dynamics and sperm release

2022 ◽  
Vol 3 (1) ◽  
pp. 101020
Author(s):  
Tushna Kapoor ◽  
Pankaj Dubey ◽  
Krishanu Ray
Keyword(s):  
Time Lapse ◽  
Actin Dynamics ◽  
Sperm Release ◽  
Drosophila Testis ◽  
Time Lapse Imaging

scholarly journals Atypical septate junctions maintain the somatic enclosure around maturing spermatids and prevent premature sperm release in Drosophila testis

2018 ◽  
Author(s):  
Pankaj Dubey ◽  
Tushna Kapoor ◽  
Samir Gupta ◽  
Seema Shirolikar ◽  
Krishanu Ray
Keyword(s):  
Tight Junctions ◽  
Somatic Cells ◽  
Septate Junction ◽  
Septate Junctions ◽  
Discs Large ◽  
Cyst Cells ◽  
Drosophila Testis ◽  
Summary Statement ◽  
Premature Release ◽  
Junction Proteins

AbstractTight junctions prevent the paracellular flow and maintain cell polarity in an epithelium. These are also essential for maintaining the blood-testis-barrier involved in regulating sperm differentiation. Septate junctions are orthologous to the tight junctions in insects. In Drosophila testis, major septate junction components co-localize at the interface of germline and somatic cells initially and then condense between the two somatic cells in a cyst after germline meiosis. Their localization is extensively remodeled in subsequent stages. We find that characteristic septate junctions are formed between the somatic cyst cells at the elongated spermatid stage. Consistent with the previous reports, knockdown of essential junctional components, Discs-large-1 and Neurexin-IV, in the somatic cyst cells, during the early stages, disrupted sperm differentiation beyond the spermatocyte stage. Somatic knockdown of these proteins during the final stages of spermatid maturation caused premature release of spermatids inside the testes, resulting in partial loss of male fertility. These results indicate the importance of maintaining mechanical integrity of the somatic enclosure during spermatid coiling and release in Drosophila testis. It also highlights the functional similarity with the tight junction proteins during spermatogenesis in mammalian testes.Summary statementDubey et al., showed that septate junctions stitch the somatic enclosure around maturing spermatids in Drosophila testis. Maintaining the integrity of this junction is essential for proper release of spermatids.

208 Sperm Retention, Storage and Release from the Oviduct: A Story of Sugars, Steroids, and Channels

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 113-114
Author(s):  
David J Miller
Keyword(s):  
Reproductive Tract ◽  
Female Reproductive Tract ◽  
Sperm Protein ◽  
Cumulus Oocyte Complex ◽  
Sperm Release ◽  
Normal Increase ◽  
Complex Origin

Abstract Because mating is not always synchronized with ovulation, females from many species store sperm in the female reproductive tract until ovulation and fertilization. This may be done for short periods, a day or two for swine and cattle, or longer periods. Other mammals, such as some species of bats, store sperm for several months. Chickens and turkeys store sperm for 2–4 weeks and queens of some species of insects store sperm for over a decade in specialized structures. How sperm are retained, kept fertile for varying times and released is unclear. We have identified two specific carbohydrate motifs that are abundant in the porcine oviduct that bind and retain sperm in the isthmus. When immobilized, these two glycans lengthen sperm lifespan and suppress the normal increase in intracellular Ca2+ that normally accompanies capacitation. Porcine sperm can be released from oviduct cells and immobilized glycans by progesterone, perhaps of ovarian or cumulus-oocyte complex origin, which activates CatSper, a sperm-specific Ca2+ channel. Progesterone, as well as other compounds that stimulate hyperactivated motility, trigger sperm release, suggesting that hyperactivated motility is sufficient to release porcine sperm from oviduct glycans. We also have found that blocking proteasome-induced sperm protein lysis diminishes the number of sperm released from oviduct glycans. Finally, a transcriptomic approach has identified several groups of genes that are differentially regulated in both bovine and porcine oviducts from estrus animals that are storing sperm compared to oviducts from diestrus animals. This provides clues about how sperm lifespan is extended during storage.

Wnt6 regulates the homeostasis of the stem cell niche via Rac1-and Cdc42-mediated noncanonical Wnt signalling pathways in Drosophila testis

2021 ◽  
Vol 402 (1) ◽  
pp. 112511
Author(s):  
Min Wang ◽  
Xiaojin Luan ◽  
Yidan Yan ◽  
Qianwen Zheng ◽  
Wanyin Chen ◽  
...  
Keyword(s):  
Stem Cell ◽  
Stem Cell Niche ◽  
Wnt Signalling ◽  
Signalling Pathways ◽  
Drosophila Testis ◽  
Cell Niche

Topographical variations in the structure of the smooth septate junction

1979 ◽  
Vol 37 (1) ◽  
pp. 373-389
Author(s):  
H.B. Skaer ◽  
J.B. Harrison ◽  
W.M. Lee
Keyword(s):  
Musca Domestica ◽  
Functional Significance ◽  
Freeze Fracture ◽  
Rhodnius Prolixus ◽  
Malpighian Tubules ◽  
Septate Junction ◽  
Lanthanum Hydroxide ◽  
Septate Junctions ◽  
Standard Fixation

Smooth septate junctions in the midgut of Musca domestica and in Malpighian tubules of both Musca and Rhodnius prolixus are described. Details of the structures revealed after standard fixation, fixation in the presence of the stain, lanthanum hydroxide, and after freeze-fracture are discussed in the light of models previously put forward to explain the interrelations of the images obtained by these different methods. The organization of the junction between cells of the midgut varies in the apical-to-basal axis. At the apical border the septa (or ridges in freeze-fracture replicas) are packed tightly and follow an undulating but strictly parallel course. This packing loosens towards the middle of the junction until, at its basal extremity, the septa (ridges in replicas) are widely separated and follow independent meandering courses. That these features are found both in lanthanum-infiltrated specimens and freeze-fracture replicas allows a correlation to be made between the septa and the freeze-fracture ridges. The functional significance of these smooth septate junctions is discussed.

The permeability properties of septate junctions in Malpighian tubules of Rhodnius

1987 ◽  
Vol 88 (2) ◽  
pp. 251-265 ◽  
Author(s):  
H.B. Skaer ◽  
S.H. Maddrell ◽  
J.B. Harrison
Keyword(s):  
Structural Characteristics ◽  
Malpighian Tubule ◽  
Malpighian Tubules ◽  
Septate Junctions ◽  
Blood Sucking ◽  
Effects Of Ph ◽  
Intercellular Clefts ◽  
Luminal Flow ◽  
Tubule Cells ◽  
Positively Charged

This paper describes the structural characteristics and permeability properties of the smooth septate junctions between the upper Malpighian tubule cells of a blood-sucking bug, Rhodnius prolixus. The permeability of the paracellular route was tested only for solutes that could be demonstrated not to cross the epithelium via the cellular route. The intercellular clefts were readily permeated by sucrose, inulin and polyethylene glycol (PEG), showing a higher permeability to molecules of smaller radius (PEG versus sucrose). Negatively charged molecules permeated the clefts more readily than positively charged ones. The effects of pH, urea and luminal flow rate on permeability were studied. The results are discussed in relation to the physiological tightness of the Malpighian tubules to certain solutes and to its function as an excretory epithelium.

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