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| 2. |
- Alvarez-Rodriguez, Manuel, et al.
(författare)
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Effect of colloid (Androcoll-Bear, Percoll, and PureSperm) selection on the freezability of brown bear (Ursus arctos) sperm
- 2016
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Ingår i: Theriogenology. - : ELSEVIER SCIENCE INC. - 0093-691X .- 1879-3231. ; 85:6, s. 1097-1105
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Tidskriftsartikel (refereegranskat)abstract
- The development of a species-specific conservation protocol that involves artificial insemination with frozen semen needs to validate an effective methodology for freezing semen. Colloid centrifugation has been suggested and widely applied as an effective tool for selecting animal spermatozoa for artificial breeding. The objective of the present study was to compare different methods of centrifugation, single layer using Androcoll-Bear and Percoll and double layer using PureSperm 100 (in two different discontinuous gradients 40%-80% and 45%-90%), for the selection of fresh brown bear sperm samples. In the before freezing group, all selected samples showed a higher progressive motility and viability (except Percoll for motility 43.0 +/- 5.3 [P < 0.051); all colloids except PureSperm 45/90% rendered samples with fewer damaged acrosomes. In the after thawing group, all tested centrifugation colloids showed a good capacity to decrease the number of damaged acrosomes. Furthermore, PureSperm treatment (45/90%) resulted in an increase in apoptotic-like changes not only immediately after thawing but also after the incubation test, leading us to suggest that this gradient could induce some kind of deleterious effects on the sperm samples. On the other hand, PureSperm treatment (40/80%) yielded a quality preservation capacity similar to Androcoll-Bear in number of damaged acrosomes, different relative to the control (control, 5.3 +/- 0.6; PureSperm 80, 2.0 +/- 0.3; Androcoll, 2.1 +/- 0.9 [P < 0.051) but a decrease in the number of viable spermatozoa recovered after thawing relative to the control (control, 21.2 +/- 3.1; PureSperm 80, 13.7 +/- 2.7 [P < 0.051). In conclusion, Androcoll-Bear constitutes a useful tool for handling of brown bear ejaculates owing to its simple handling and procedure with a reliable sperm selection and freezability. This colloid yielded an improvement in several sperm parameters in brown bear frozen-thawed semen; the selected spermatozoa of fresh samples with this colloid showed a better resistance to freezing compared with the control sample not only for motility but also for viability. (C) 2016 Elsevier Inc. All rights reserved.
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| 3. |
- Alvarez-Rodriguez, Manuel, et al.
(författare)
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Effect of length of time post-mortem on quality and freezing capacity of Cantabric chamois (Rupicapra pyrenaica parva) epididymal spermatozoa
- 2018
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Ingår i: Animal Reproduction Science. - : ELSEVIER SCIENCE BV. - 0378-4320 .- 1873-2232. ; 198, s. 184-192
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Tidskriftsartikel (refereegranskat)abstract
- Genome Resource Banks are keystones in the ex-situ conservation of wild species. Post-mortem (PM) collection of epididymal spermatozoa is an opportunistic and valuable source of germplasm, the time from the death of the animal limits its use. Seeking to improve germplasm preservation strategies for the chamois (Rupicapra sp.), the effect of PM time on epididymal sperm quality and freezability was studied using the Cantabrian chamois. Samples were classified according to PM collection time, up to 216 h (refrigerated), and cryopreserved (Tris-citric acid-fructose, 430 mOsm/kg, 15% egg yolk, 8% glycerol; freezing at - 20 degrees C/min). Sperm quality was assessed after recovery and post-thawing (motility by CASA, HOS test, abnormal forms, cytoplasmic droplets, and viability and acrosomal damage by flow cytometry). The sperm mass pH and osmolality showed a positive correlation with time. Total sperm motility dropped after 2 days PM, with progressivity and sperm velocities remained similar up to 3 days PM. Sperm freezability was acceptable, with the post-thawing HOST, motility, progressivity, VAP, VCL, VSL and BCF negatively correlating with PM time. Overall, chamois epidydimal samples were not adequate for preservation after 6 days PM. Freezability capacity could make these spermatozoa suitable for specific ART even if kept refrigerated for several days PM.
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| 4. |
- Munoz, P. Martin, et al.
(författare)
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Redox cycling induces spermptosis and necrosis in stallion spermatozoa while the hydroxyl radical (OH center dot) only induces spermptosis
- 2018
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Ingår i: Reproduction in domestic animals. - : WILEY. - 0936-6768 .- 1439-0531. ; 53:1, s. 54-67
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Tidskriftsartikel (refereegranskat)abstract
- Oxidative stress is a major factor explaining sperm dysfunction of spermatozoa surviving freezing and thawing and is also considered a major inducer of a special form of apoptosis, visible after thawing, in cryopreserved spermatozoa. To obtain further insights into the link between oxidative stress and the induction of apoptotic changes, stallion spermatozoa were induced to oxidative stress through redox cycling after exposure to 2-methyl-1,4-naphthoquinone (menadione), or hydroxyl radical formation after FeSO4 exposure. Either exposure induced significant increases (p amp;lt; 0.05) in two markers of lipid peroxidation: 8-iso-PGF(2) and 4-hydroxynonenal (4-HNE). While both treatments induced changes indicative of spermptosis (caspase-3 activation and decreased mitochondrial membrane potential) (p amp;lt; 0.01), menadione induced sperm necrosis and a dramatic reduction in motility and thiol content in stallion spermatozoa. Thus, we provided evidence that oxidative stress underlies spermptosis, and thiol content is a key factor for stallion sperm function.
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| 5. |
- Ortega Ferrusola, C., et al.
(författare)
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Stallion spermatozoa surviving freezing and thawing experience membrane depolarization and increased intracellular Na
- 2017
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Ingår i: Andrology. - : WILEY. - 2047-2919 .- 2047-2927. ; 5:6, s. 1174-1182
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Tidskriftsartikel (refereegranskat)abstract
- In order to gain insight of the modifications that freezing and thawing cause to the surviving population of spermatozoa, changes in the potential of the plasma membrane (Em) and intracellular Na+ content of stallion spermatozoa were investigated using flow cytometry. Moreover, caspase 3 activity was also investigated and the functionality of the Na+-K+ ATPase pump was investigated before and after freezing and thawing. Cryopreservation caused a significant (pamp;lt;0.001) increase in the subpopulation of spermatozoa with depolarized sperm membranes, concomitantly with an increase (pamp;lt;0.05) in intracellular Na+. These changes occurred in relation to activation of caspase 3 (pamp;lt;0.001). Cryopreservation reduced the activity of the Na-K+ pump and inhibition of the Na+-K+ ATPase pump with ouabain-induced caspase 3 activation. It is concluded that inactivation of Na+-K+ ATPase occurs during cryopreservation, an inhibition that could play a role explaining the accelerated senescence of the surviving population of spermatozoa.
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| 6. |
- Toohey, M., et al.
(författare)
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Characterizing sampling biases in the trace gas climatologies of the SPARC Data Initiative
- 2013
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Ingår i: Journal of Geophysical Research. - : American Geophysical Union (AGU). - 0148-0227 .- 2156-2202 .- 2169-897X .- 2169-8996. ; 118:20, s. 11847-11862
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Tidskriftsartikel (refereegranskat)abstract
- Monthly zonal mean climatologies of atmospheric measurements from satellite instruments can have biases due to the nonuniform sampling of the atmosphere by the instruments. We characterize potential sampling biases in stratospheric trace gas climatologies of the Stratospheric Processes and Their Role in Climate (SPARC) Data Initiative using chemical fields from a chemistry climate model simulation and sampling patterns from 16 satellite-borne instruments. The exercise is performed for the long-lived stratospheric trace gases O3 and H2O. Monthly sampling biases for O3 exceed 10% for many instruments in the high-latitude stratosphere and in the upper troposphere/lower stratosphere, while annual mean sampling biases reach values of up to 20% in the same regions for some instruments. Sampling biases for H2O are generally smaller than for O3, although still notable in the upper troposphere/lower stratosphere and Southern Hemisphere high latitudes. The most important mechanism leading to monthly sampling bias is nonuniform temporal sampling, i.e., the fact that for many instruments, monthly means are produced from measurements which span less than the full month in question. Similarly, annual mean sampling biases are well explained by nonuniformity in the month-to-month sampling by different instruments. Nonuniform sampling in latitude and longitude are shown to also lead to nonnegligible sampling biases, which are most relevant for climatologies which are otherwise free of biases due to nonuniform temporal sampling.
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| 7. |
- Ortega-Ferrusola, C., et al.
(författare)
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Flow cytometry in Spermatology: A bright future ahead
- 2017
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Ingår i: Reproduction in domestic animals. - : WILEY. - 0936-6768 .- 1439-0531. ; 52:6, s. 921-931
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Forskningsöversikt (refereegranskat)abstract
- Techniques such as mass spectrometry have led to unprecedented knowledge of the proteins that are present in the spermatozoa of humans and other mammals. However, in spite of their high-throughput and fractioning techniques, most of the techniques in use only offer average values for the entire sperm population. Yet, ejaculate is very heterogeneous, and average values may mask relevant biological information. The application of flow cytometry may overcome this disadvantage, allowing proteomic analysis at the single-cell level. Moreover, recent advances in cytometry, allowing multiple analyses within a single cell combined with powerful statistical tools, as an expanding subfield in spermatology, are described. The increased use of advanced flow cytometers in andrology laboratories will allow the rapid development of multiparametric, multicolour flow cytometry in andrology that will expand the clinical applications and research possibilities of flow cytometry-based proteomic approaches, especially in the subfields of clinical andrology and sperm biotechnology.
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