Mechanism of Male Gamete Motility in Araphid Pennate Diatoms from the Genus Tabularia (Bacillariophyta)

Protist ◽  
2012 ◽  
Vol 163 (3) ◽  
pp. 480-494 ◽  
Author(s):  
Nickolai A. Davidovich ◽  
Irena Kaczmarska ◽  
Sergey A. Karpov ◽  
Olga I. Davidovich ◽  
Michael L. MacGillivary ◽  
...  
Keyword(s):  
Male Gamete ◽  
Pennate Diatoms

Offsetting Effects of Wolbachia Infection and Heat Shock on Sperm Production inDrosophila simulans: Analyses of Fecundity, Fertility and Accessory Gland Proteins

Genetics ◽  
2000 ◽  
Vol 155 (1) ◽  
pp. 167-178 ◽  
Author(s):  
Rhonda R Snook ◽  
Sophia Y Cleland ◽  
Mariana F Wolfner ◽  
Timothy L Karr
Keyword(s):  
Heat Shock ◽  
Natural Populations ◽  
Adult Life ◽  
Reproductive Factors ◽  
Male Gamete ◽  
Wolbachia Infection ◽  
Accessory Gland ◽  
Sperm Production ◽  
Accessory Gland Proteins ◽  
Mating Conditions

AbstractInfection in Drosophila simulans with the endocellular symbiont Wolbachia pipientis results in egg lethality caused by failure to properly initiate diploid development (cytoplasmic incompatibility, CI). The relationship between Wolbachia infection and reproductive factors influencing male fitness has not been well examined. Here we compare infected and uninfected strains of D. simulans for (1) sperm production, (2) male fertility, and (3) the transfer and processing of two accessory gland proteins, Acp26Aa or Acp36De. Infected males produced significantly fewer sperm cysts than uninfected males over the first 10 days of adult life, and infected males, under varied mating conditions, had lower fertility compared to uninfected males. This fertility effect was due to neither differences between infected and uninfected males in the transfer and subsequent processing of accessory gland proteins by females nor to the presence of Wolbachia in mature sperm. We found that heat shock, which is known to decrease CI expression, increases sperm production to a greater extent in infected compared to uninfected males, suggesting a possible link between sperm production and heat shock. Given these results, the roles Wolbachia and heat shock play in mediating male gamete production may be important parameters for understanding the dynamics of infection in natural populations.

TWO-GENERATION ANALYSIS OF POLLEN FLOW ACROSS A LANDSCAPE. I. MALE GAMETE HETEROGENEITY AMONG FEMALES

Evolution ◽  
2001 ◽  
Vol 55 (2) ◽  
pp. 260 ◽  
Author(s):  
Peter E. Smouse ◽  
Rodney J. Dyer ◽  
Robert D. Westfall ◽  
Victoria L. Sork
Keyword(s):  
Male Gamete ◽  
Pollen Flow

Ultrastructural Localization of Intracellular Calcium During Spermatogenesis of Sterlet (Acipenser ruthenus)

2016 ◽  
Vol 22 (6) ◽  
pp. 1155-1161 ◽  
Author(s):  
Amin Golpour ◽  
Martin Pšenička ◽  
Hamid Niksirat
Keyword(s):  
Intracellular Calcium ◽  
Developmental Stages ◽  
Physiological Function ◽  
Male Gamete ◽  
Ultrastructural Localization ◽  
Acrosomal Vesicle ◽  
Acipenser Ruthenus ◽  
Calcium Deposits ◽  
Late Stages ◽  
Sterlet Acipenser Ruthenus

AbstractCalcium regulates many intracellular events such as growth and differentiation during different stages of gamete development. The aim of this study was to localize and quantify the intracellular distribution of calcium during different developmental stages of spermatogenesis in sterlet, Acipenser ruthenus, using a combined oxalate–pyroantimonate technique. The distribution of calcium was described in spermatogonium, spermatocyte, spermatid, and spermatozoon stages. In the spermatogonium and spermatocyte, calcium deposits were mainly localized in the nucleus and cytoplasm. The spermatid had calcium in the nucleus, developing acrosomal vesicle, and cytoplasm. Intracellular calcium transformed from scattered deposits in spermatogonia and spermatocyte stages into an unbound form in spermatid and the spermatozoon. The proportion of area covered by calcium increased significantly (p<0.05) from early to late stages of spermatogenesis. The largest proportion of area covered by calcium was observed in the nucleus of the spermatozoon. In conclusion, although most of the intracellular calcium is deposited in limited areas of the spermatogonium and spermatocyte, it is present an unbound form in the larger area of spermatids and spermatozoa which probably reflects changes in its physiological function and homeostasis during the process of male gamete production in spermatogenesis.

Observations on the ecology of hybridisation in the clubmosses (Lycopodiaceae)

1985 ◽  
Vol 86 ◽  
pp. 245-251 ◽  
Author(s):  
Benjamin Øllgaard
Keyword(s):  
Male Gamete ◽  
Interspecific Hybridisation ◽  
Parent Species ◽  
Spore Dispersal ◽  
Population Densities ◽  
Ecological Conditions ◽  
Highly Effective ◽  
Subterranean Habitat

SynopsisEcological conditions for intergametophytic mating and interspecific hybridisation in the clubmosses are discussed. Several features, including the number of recorded hybrids, records of gametophyte population densities, and conditions for movement of the male gamete in the soil, indicate that intergametophytic mating in Lycopodium is not especially impeded by the subterranean habitat, as has been commonly assumed. The evidence from one site indicates highly effective spore dispersal, and a greater ecological tolerance than expected for the species involved. Two cases are discussed in which hybrids have been formed between ecologically and/or taxonomically very different parent species, in the absence of one parent sporophyte, or with one of the parent species sporophyte poorly adapted to the hybrid habitat. The protected, relatively uniform, subterranean gametophyte habitat is thought to account for successful gametophyte growth and hybridisation between species of widely different sporophyte ecology.

scholarly journals Melatonin Effect on Cryopreserved Sperm Cells of Crioulo Stallions

2020 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Eraldo L Zanella
Keyword(s):  
Plasma Membrane ◽  
Sperm Motility ◽  
Membrane Integrity ◽  
Male Gamete ◽  
The Body ◽  
Cellular Damage ◽  
Ros Generation ◽  
Sperm Cells ◽  
Beneficial Effects ◽  
Endogenous Antioxidant

The freezing/thawing process of spermatozoa can cause cellular damage to the male gamete, decreasing the fertilization potential due to the increase in the production of reactive oxygen species (ROS). Melatonin is a potent endogenous antioxidant that protects the body against the damage caused by ROS. This study has evaluated different melatonin concentrations on the sperm viability of cryopreserved semen of Crioulo stallions. For that, three ejaculates were collected from five stallions diluted in a commercial extender followed by centrifugation and resuspension in a commercial freezing extender supplemented with 0; 1.25; 2.5. 5mM of Melatonin before the cryopreservation process. After thawing, the evaluation was performed assessing motility and flow cytometry evaluations: the plasma membrane integrity (PI), the integrity of the acrosomal membrane (FITC-PNA), mitochondrial membrane potential (JC1), and ROS generation (DCF-DA). Our results showed that sperm motility in the group without Melatonin and the 1.25mM group did not show the difference; however, the groups 2.5mM and 5mM presented a reduction in sperm motility. The 1.25 mM concentration was able to protect the plasma membrane during the cryopreservation process, in addition to showing a significant reduction in the production of ROS and increasing the percentage of sperm with integral acrosome. It can also be seen that high concentrations of Melatonin did not show beneficial effects. In conclusion, the addition of 1.25 mM of the Melatonin in Crioulo sperm cells showed to have a protective effect on the sperm cell during cryopreservation.

Thraustochytrid protists in Antarctic fast ice?

1993 ◽  
Vol 5 (3) ◽  
pp. 279-280 ◽  
Author(s):  
Franz Riemann ◽  
Karsten Schaumann
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Short Note ◽  
Weddell Sea ◽  
Lower Section ◽  
Fast Ice ◽  
Arctic Ice ◽  
Pennate Diatoms

Sea ice provides a habitat for a conspicuous and productive assemblage of autotrophic microalgae and for heterotrophs ranging from bacteria to vertebrates (Horner 1990, Garrison 1991). With the exception of a reference to chytridiaceous fungi that were found infecting Arctic ice diatoms (Horner 1977) and a note in a cruise report (Schnack-Schiel 1987, p. 153), it appears that fungi and similar organisms have until now not been mentioned as members of the heterotrophic sea ice community. In the present short note we report on the abundant occurrence of apparently thraustochytrid fungus-like protists associated with mucilage tubes of pennate diatoms, encountered in the lower section of a fast ice core drilled close to the southern shelf ice margin of the Weddell Sea.

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