Phosphatidylserine Membrane Translocation in Human Spermatozoa: Topography in Membrane Domains and Relation to Cell Vitality

The complex structure of the human spermatozoa membrane comprises five topographic domains. Transmembrane asymmetry of the distribution of phospholipids including phosphatidylserine (PS) is considered a marker of cell activity. The objective of the study was to determine which cytomembrane domains of human spermatozoa are involved in PS membrane translocation and to identify the possible relationship of PS translocation with spermatozoa morphology and vitality. In normozoospermic semen of 35 donors, annexin-V labeling with fluorescein determined PS translocation. Propidium iodide staining distinguished between vital and dead spermatozoa. Three types of PS membrane translocation have been distinguished: (1) in the midpiece, (2) in the acrosomal part and (3) simultaneously in the midpiece and acrosomal part. In morphologically normal vital spermatozoa, PS translocation occurred in the midpiece but never in the equatorial region. In dead spermatozoa, simultaneous PS translocation in the midpiece and acrosomal part was most often observed. The difference between proportions of, respectively, vital and dead spermatozoa presenting PS translocation located in different domains was significant (P < 0.0001). In vital cells, there was no difference in PS translocation prevalence between morphologically normal and abnormal spermatozoa (P > 0.05). The strict relation of PS translocation to specific membrane domains indicates functional specificity. It seems doubtful to include this phenomenon in physiological mechanisms of elimination of abnormal spermatozoa

17β-estradiol and xenoestrogens reveal synergistic effect on mitochondria of human sperm

Objectives: The aim of the study was to investigate the influence of 17β-estradiol (main endogenous estrogen) and selected xenoestrogens (genistein, bisphenol-A), individually and in combination, on the mitochondrial function of human sper­matozoa. In natural environment, human beings are exposed to multiple xenoestrogens, so their impact is combined with endogenous steroids. Material and methods: The effects of ligands on human spermatozoa were assessed regarding the following phenomena: spermatozoa vitality (propidium iodide staining), phosphatidylserine membrane translocation (staining with annexin V marked with fluorescein), mitochondrial membrane potential (using JC-1 fluorochrome), and production of superoxide anion in mitochondria (using MitoSOX RED dye). Results: Two-hour incubation of spermatozoa with 17β-estradiol, genistein, and bisphenol-A neither altered cell vitality nor stimulated phosphatidylserine membrane translocation. Incubation of spermatozoa with 17β-estradiol or bisphenol-A sepa­rately, as well as incubation with the three ligands simultaneously, resulted in altered mitochondrial membrane potential. Spermatozoa incubation with the three ligands significantly increased the mitochondrial superoxide anion level. Conclusions: It seems safe to conclude that human spermatozoa mitochondria are target cell structures for both, 17β-estradiol and xenoestrogens. The reaction to the 17β-estradiol and xenoestrogens mixture suggests a synergistic mechanism of action. Xenoestrogens may increase the sensitivity of spermatozoa to 17β-estradiol

Reduced levels of intracellular calcium releasing in spermatozoa from asthenozoospermic patients

<p>Abstract</p> <p>Background</p> <p>Asthenozoospermia is one of the most common findings present in infertile males characterized by reduced or absent sperm motility, but its aetiology remains unknown in most cases. In addition, calcium is one of the most important ions regulating sperm motility. In this study we have investigated the progesterone-evoked intracellular calcium signal in ejaculated spermatozoa from men with normospermia or asthenozoospermia.</p> <p>Methods</p> <p>Human ejaculates were obtained from healthy volunteers and asthenospermic men by masturbation after 4–5 days of abstinence. For determination of cytosolic free calcium concentration, spermatozoa were loaded with the fluorescent ratiometric calcium indicator Fura-2.</p> <p>Results</p> <p>Treatment of spermatozoa from normospermic men with 20 micromolar progesterone plus 1 micromolar thapsigargin in a calcium free medium induced a typical transient increase in cytosolic free calcium concentration due to calcium release from internal stores. Similar results were obtained when spermatozoa were stimulated with progesterone alone. Subsequent addition of calcium to the external medium evoked a sustained elevation in cytosolic free calcium concentration indicative of capacitative calcium entry. However, when progesterone plus thapsigargin were administered to spermatozoa from patients with asthenozoospermia, calcium signal and subsequent calcium entry was much smaller compared to normospermic patients. As expected, pretreatment of normospermic spermatozoa with both the anti-progesterone receptor c262 antibody and with progesterone receptor antagonist RU-38486 decreased the calcium release induced by progesterone. Treatment of spermatozoa with cytochalasin D or jasplakinolide decreased the calcium entry evoked by depletion of internal calcium stores in normospermic patients, whereas these treatments proved to be ineffective at modifying the calcium entry in patients with asthenozoospermia.</p> <p>Conclusion</p> <p>Our results suggest that spermatozoa from asthenozoospermic patients present a reduced responsiveness to progesterone.</p

Landslide morphology of the south-eastern part of the Wałbrzyskie Mountains, Middle Sudetes

The occurrence of landforms induced by large-scale mass movements has never been reported from the SE part of the Wałbrzyskie Mts., despite detailed geological field mapping carried out twice in the 20th century. This paper provides the first description of landslide-affected slopes in this area, recognized through the combination of LiDAR DEM interpretation and field work. Fifteen landslides have been identified, ranging in size from less than 1 ha to 10.44 ha. Morphological signatures suggest that they represent various types, including minor translational slides, larger rotational complexes and valley-confined flowslides. Closed depressions typify several landslides. In a few instances the valley blocking by landslides can be inferred