scholarly journals Sperm gatekeeping: 3D imaging reveals a constricted entrance to zebra finch sperm storage tubules

2018 ◽  
Author(s):  
T. Mendonca ◽  
A. J. Cadby ◽  
N. Hemmings
Keyword(s):  
Zebra Finch ◽  
Reproductive Tract ◽  
Captive Breeding ◽  
3D Structure ◽  
Three Dimensional ◽  
Sperm Storage ◽  
Conservation Strategies ◽  
Selective Plane Illumination Microscopy ◽  
Storage Organs ◽  
Sperm Storage Tubules

AbstractFemales across many internally fertilising taxa store sperm, often in specialised storage organs in their reproductive tracts. In birds, several hundred sperm storage tubules exist in the utero-vaginal junction of the oviduct and there is growing evidence that sperm storage in these tubules is selective. The mechanisms underlying female sperm storage in birds remain unknown due to our limited ability to make three dimensional, live observations inside the large, muscular avian oviduct. Here, we describe a new application of fluorescence selective plane illumination microscopy to optically section oviduct tissue from zebra finchTaeniopygia guttatafemales label-free, by harnessing tissue autofluorescence. Our data provide the first description of the 3D structure of sperm storage organs in any vertebrate and reveal the presence of gate-like constricted openings that may play a role in sperm selection.Statement of SignificanceFemale birds can store sperm in microscopic tubular structures in their reproductive tract for up to several months, depending on species. Studying these sperm storage tubules has been a major challenge due to the muscular and opaque nature of reproductive tracts in birds. We have developed a new method for imaging live reproductive tract tissue using selective plane illumination microscopy, a fluorescence microscopy technique. From these images, we could extract three-dimensional measurements of sperm storage tubules and found these structures to have a gate-like constriction, providing evidence that females can actively select sperm at storage and ultimately influence the paternity of her offspring. Understanding these reproductive adaptations can help improve captive breeding programs and similar conservation strategies.

scholarly journals Acp36DE is required for uterine conformational changes in mated Drosophila females

2009 ◽  
Vol 106 (37) ◽  
pp. 15796-15800 ◽  
Author(s):  
Frank W. Avila ◽  
Mariana F. Wolfner
Keyword(s):  
Reproductive Success ◽  
Sperm Competition ◽  
Conformational Changes ◽  
Reproductive Tract ◽  
Sperm Storage ◽  
Internal Fertilization ◽  
Content Type ◽  
Storage Organs ◽  
Subsequent Storage ◽  
And Behavior

In a multitude of animals with internal fertilization, including insects and mammals, sperm are stored within a female's reproductive tract after mating. Defects in the process of sperm storage drastically reduce reproductive success. In Drosophila males, “Acp” seminal proteins alter female postmating physiology and behavior, and are necessary for several aspects of sperm storage. For example, Acps cause a series of conformational changes in the mated female's reproductive tract that occur during and immediately after mating. These conformational changes have been hypothesized to aid both in the movement of sperm within the female and in the subsequent storage of those sperm. We used RNAi to systematically knock down several Acps involved in sperm storage to determine whether they played a role in the mating-induced uterine conformational changes. Mates of males lacking the glycoprotein Acp36DE, which is needed for the accumulation of sperm in the storage organs, fail to complete the full sequence of the conformational changes. Our results show that uterine conformational changes are important for proper accumulation of sperm in storage and identify a seminal protein that mediates these changes. Four Acps included in this study, previously shown to affect sperm release from storage (CG9997, CG1656, CG1652, and CG17575), are not necessary for uterine conformational changes to occur. Rather, consistent with their role in later steps of sperm storage, we show here that their presence can affect the outcome of sperm competition situations.

scholarly journals Differential sperm storage by female zebra finches Taeniopygia guttata

2017 ◽  
Vol 284 (1860) ◽  
pp. 20171032 ◽  
Author(s):  
Nicola Hemmings ◽  
Tim Birkhead
Keyword(s):  
Female Choice ◽  
Reproductive Tract ◽  
Fertilization Success ◽  
Sperm Storage ◽  
Taeniopygia Guttata ◽  
Female Reproductive Tract ◽  
Cryptic Female Choice ◽  
Zebra Finches ◽  
Novel Technique ◽  
Sperm Storage Tubules

When females mate promiscuously, female sperm storage provides scope to bias the fertilization success towards particular males via the non-random acceptance and utilization of sperm. The difficulties observing post-copulatory processes within the female reproductive tract mean that the mechanisms underlying cryptic female choice remain poorly understood. Here, we use zebra finches Taeniopygia guttata , selected for divergent sperm lengths, combined with a novel technique for isolating and extracting sperm from avian sperm storage tubules (SSTs), to test the hypothesis that sperm from separate ejaculates are stored differentially by female birds. We show that sperm from different inseminations enter different SSTs in the female reproductive tract, resulting in almost complete segregation of the sperm of competing males. We propose that non-random acceptance of sperm into SSTs, reflected in this case by sperm phenotype, provides a mechanism by which long sperm enjoy enhanced fertilization success in zebra finches.

scholarly journals Sperm Gatekeeping: 3D Imaging Reveals a Constricted Entrance to Zebra Finch Sperm Storage Tubules

2019 ◽  
Vol 117 (11) ◽  
pp. 2180-2187
Author(s):  
Tania Mendonca ◽  
Ashley J. Cadby ◽  
Nicola Hemmings
Keyword(s):  
Zebra Finch ◽  
3D Imaging ◽  
Sperm Storage ◽  
Sperm Storage Tubules

scholarly journals A trade-off between thickness and length in the zebra finch sperm mid-piece

2018 ◽  
Vol 285 (1883) ◽  
pp. 20180865 ◽  
Author(s):  
Tania Mendonca ◽  
Tim R. Birkhead ◽  
Ashley J. Cadby ◽  
Wolfgang Forstmeier ◽  
Nicola Hemmings
Keyword(s):  
Zebra Finch ◽  
Energy Content ◽  
Three Dimensional ◽  
Negative Relationship ◽  
Taeniopygia Guttata ◽  
Dimensional Approach ◽  
Mitochondrial Density ◽  
Trade Off ◽  
Transmission Electron ◽  
Selective Plane Illumination Microscopy

The sperm mid-piece has traditionally been considered to be the engine that powers sperm. Larger mid-pieces have therefore been assumed to provide greater energetic capacity. However, in the zebra finch Taeniopygia guttata , a recent study showed a surprising negative relationship between mid-piece length and sperm energy content. Using a multi-dimensional approach to study mid-piece structure, we tested whether this unexpected relationship can be explained by a trade-off between mid-piece length and mid-piece thickness and/or cristae density inside the mitochondrial helix. We used selective plane illumination microscopy to study mid-piece structure from three-dimensional images of zebra finch sperm and used high-resolution transmission electron microscopy to quantify mitochondrial density. Contrary to the assumption that longer mid-pieces are larger and therefore produce or contain a greater amount of energy, our results indicate that the amount of mitochondrial material is consistent across mid-pieces of varying lengths, and longer mid-pieces are simply proportionately ‘thinner’.

Genetic evidence for multiple paternity in the critically endangered Cuban crocodile (Crocodylus rhombifer)

2016 ◽  
Vol 37 (3) ◽  
pp. 273-281 ◽  
Author(s):  
Yoamel Milián-García ◽  
Evelyn L. Jensen ◽  
Sheila Ribalta Mena ◽  
Etiam Pérez Fleitas ◽  
Gustavo Sosa Rodríguez ◽  
...  
Keyword(s):  
Mating System ◽  
Captive Breeding ◽  
Multiple Paternity ◽  
Sperm Storage ◽  
Critically Endangered ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Genetic Studies ◽  
Factors Influencing ◽  
Polygynous Mating System

Conservation strategies can be most effective when factors influencing the persistence of populations are well-understood, including aspects of reproductive biology such as mating system. Crocodylians have been traditionally associated with a polygynous mating system, with genetic studies revealing multiple paternity of clutches in several species. The endemic Cuban crocodile,Crocodylus rhombifer, is currently listed as Critically Endangered, and is one of the least understood crocodylian species in terms of its mating behavior. Here, we tested a hypothesis of multiple paternity in the Cuban crocodile by collecting genotypic data at nine microsatellite loci for 102 hatchlings from five nests sampled at the Zapata Swamp captive breeding facility and analyzing them in relation to data previously collected for 137 putative parents. All five nests showed evidence of multiple paternity based on the numbers of alleles per locus, with sibship analyses reconstructing all nests as having four to six full-sib family groups. Accordingly, mean pairwise relatedness values per nest ranged from 0.21 to 0.39, largely intermediate between theoretical expected values for half-siblings (0.25) and full-siblings (0.50). It is not possible to differentiate whether the multiple paternity of a nest was due to multiple matings during the same breeding season, or a result of sperm storage. Our results reveal that theC. rhombifermating system is likely best characterized as promiscuous and suggest that the standard practice of enforcing a 1:2 sex ratio at the captive breeding facility should be altered in order to better maintain a demographically and genetically healthy ex situ population.

Numbers and Distribution of Sperm in the Uterovaginal Sperm Storage Tubules of the Zebra Finch

The Condor ◽  
1990 ◽  
Vol 92 (2) ◽  
pp. 508 ◽  
Author(s):  
T. R. Birkhead ◽  
J. E. Pellatt ◽  
F. M. Hunter
Keyword(s):  
Zebra Finch ◽  
Sperm Storage ◽  
Sperm Storage Tubules

Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study

1977 ◽  
Vol 35 ◽  
pp. 668-669
Author(s):  
Mai M. Said ◽  
Ramesh K. Nayak ◽  
Randall E. McCoy
Keyword(s):  
Guinea Pig ◽  
Reproductive Tract ◽  
Three Dimensional ◽  
Female Reproductive Tract ◽  
Human Female ◽  
Surface Ultrastructure ◽  
Transmission Electron ◽  
Sem Study ◽  
Uterine Mucosa ◽  
Group 1

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

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