| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Pena, F.J., et al.
(författare)
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Detection of early changes in sperm membrane integrity pre-freezing can estimate post-thaw quality of boar spermatozoa
- 2007
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Ingår i: Animal Reproduction Science. - : Elsevier Masson. - 0378-4320 .- 1873-2232. ; 97:1-2, s. 74-83
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Tidskriftsartikel (refereegranskat)abstract
- A recently developed triple staining (SNARF-1/YO-PRO-1/ethidium homodimer) was used to assess early changes in boar sperm membrane integrity (MI) with the results of cryopreservation procedures and to seek for correlations among MI-spermatozoa in pre-freeze semen and its freezeability. Ejaculates from five boars were evaluated in the fresh and frozen-thawed (FT) state, and its freezeability defined as % of membrane intactness, MI% (MI% = % of FT-spermatozoa with intact membranes x 100 divided by the % of prefreeze spermatozoa with intact membranes) estimated. Significant differences were found among boars for freezeability (MI%) and motility post-thaw (%). Interestingly, significant correlations were found between the percentage of YO-PRO-1-positive spermatozoa and freezeability (R = 0.440, p less than 0.01), indicating this new triple staining can be used to safely disclose among ejaculates prior to freezing. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Rodriguez-Martinez, Heriberto, et al.
(författare)
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Influence of seminal plasma on the kinematics of boar spermatozoa during freezing
- 2008
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 70:8, s. 1242-1250
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Tidskriftsartikel (refereegranskat)abstract
- Sperm motolity is, for its relation to cell viability and fertility, a central component of the spermiogram, where consideration of motion patterns allows discrimination of sub-populations among boar spermatozoa. Extension and cryo-preservation imposes changes in these patterns in connection to handling, additives, temperature changes and the removal of boar seminal plasma (BSP) which apparently makes spermatozao susceptible to xodative stress, thus affecting survival and motility post-thaw. Detailed kinematic analyses during sperm cooling are sparse, particularly when considering the instrumentation and settings used for analyses, the effect of extenders, and of the BSP the processed spermatozoa are exposed to. Spermatozoa present in the first collectable 10 mL of the sperm-rich fraction of the ejaculate (portion 1. P1-BSP), have shown an increased ability to sustain motility during and after cryo-preservation than spermatozoa immersed in the rest of the ejaculate (portion 2, P2). When P2-spermatozoa were cleansed from their BSP and exposed for 60 min to pooled P1-BSP, their motility post-thaw increased to similar levels as P1-spermatozoa. This BSP-influence is sire-dependent, presumably related to the protein concentration in the different ejaculate poriton,s andapparently unrealted to changes in membrane integrity or membrane stability through conventiona, controlled cooling. (C) 2008 Elsevier Inc. All rights reserved.
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| 5. |
- Saravia, F., et al.
(författare)
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Differences in boar sperm head shape and dimensions recorded by computer-assisted sperm morphometry are not related to chromatin integrity
- 2007
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 68:2, s. 196-203
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Tidskriftsartikel (refereegranskat)abstract
- Although sperm head shape and relative dimensions are considered reliable indicators of sperm quality, their quantification is most often operator-driven, e.g., subjective. Artificial insemination semen doses from 35 mature stud boars of known fertility and belonging to three breeds and two hybrid breeds (Duroc, Large White, Landrace, respectively, Yorker and Risco) were used in this study. Sperm samples were extended to 100 x 10(6) Cells per mL and 10 mu L of the sperm suspension used to made smears which, stained, were examined using phase contrast microscopy interfaced with an automated sperm morphology analyzer (ASMA, 2 ISAS (R)). Each sperm head was measured for four primary parameters [area (A) mu m(2), perimeter (P) mu m, length (L) mu m, width (M mu m], and four derived parameters of head shape [(L/W, (4 pi A/P-2), ((L - W/(L + M), (pi LW/4A)]. Definition of head size was statistically performed. The threshold for each class was established on the basis of the area values, considering the 25th percentile as small and the 75th percentile as large spermatozoa. In a second step, sperm head shape was determined as normal, elliptic, abnormal (rugose) contour, long or irregular and percentiles set as above to define spermatozoa with normal values for each shape parameter. Significant differences were found among breeds in the size of morphologically normal spermatozoa, which were significantly larger and more elliptic (P less than 0.001) in the Duroc breed. Sperm chromatin integrity was studied using the SCSA-assay, with significant differences observed in the degree of fragmentation intensity (DFI) although this value was consistently low in all animals studied. The hereby-validated ASMA was able to determine significant differences in sperm shape and dimensions among breeds, which were not accompanied by deviations in chromatin structure neither within nor between fertile AI-boars. (c) 2007 Elsevier Inc. All rights reserved.
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| 6. |
- Tejerina, F., et al.
(författare)
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Assessment of motility of ejaculated, liquid-stored boar spermatozoa using computerized instruments
- 2008
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 69:9, s. 1129-1138
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Tidskriftsartikel (refereegranskat)abstract
- Visual-motility assessment is a tool used to determine the quality of boar ejaculates. This method is subjective by nature, and consequently, computer-assisted sperm analysis (CASA), with different software designs, has been developed for more objective assessment using conventional image analysis or particle counting. In the present study, we compared the results of sperm analysis using a conventional CASA system (Cell Motion Analyzer, SM-CMA (TM)), with those using a novel software (QualiSperm (TM)) and those of visual assessment performed by two operators. Ejaculates were collected weekly from four Swedish Landrace boars for 4 weeks. Each ejaculate was divided into three aliquots of different sperm concentration (300, 125, and 40 million spermatozoa/mL) and stored at similar to 17 degrees C for 96 h. Only samples at 40 million spermatozoa/mL concentration were analyzed using both automated systems; for the remaining concentrations, the SM-CMA (TM) was not used due to its inability to examine higher sperm concentrations. The number of spermatozoa analyzed was highest for the QualiSperm (TM) (similar to 300-5000 spermatozoa), followed by the SM-CMA (TM) (similar to 200 spermatozoa), and lastly, by subjective motility evaluation (similar to 100 spermatozoa). There was a time-course decrease in motility of the liquid-stored semen, detectable by either computerized method. Although the percentage of motile spermatozoa measured by the two automated systems correlated well (r greater than= 0.75), there was disagreement between operators. In conclusion, because of the lower degree of variation, the numbers of spermatozoa analyzed, and the speed of analysis (similar to 1 min per sample), QualiSperm (TM) appears to be a suitable instrument for routine work, provided it maintains stability and is available at an affordable price. (C) 2008 Elsevier Inc. All rights reserved.
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| 7. |
- Ballester, J., et al.
(författare)
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Post-thaw viability of bull AI-doses with low-sperm numbers
- 2007
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 68:6, s. 934-943
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Tidskriftsartikel (refereegranskat)abstract
- Use of AI-doses containing low-sperm numbers are increasingly been used to optimise use of elite bulls as well as to accommodate an eventual wider application of sex-sorted semen. Since spermatozoa might, however, suffer from high extension rates, thus compromising fertility, this study evaluated the post-thaw sperm quality of semen from commercial progeny-tested, high-ranked AI-sires whose semen was within acceptable limits of normality, frozen in a split-design to 15 (control, 15M) or 2 x 106 total spermatozoa (treatment, 2M) per straw. Assessment post-thaw included computer-evaluated sperm motility (CASA), membrane integrity (SYBR-14/PI), membrane stability (Annexin-V/Pl), acrosome integrity (Carboxy-SNARF-1/PI/ FITC-PSA), and chromatin integrity (AO of in situ acid-induced DNA denaturation). High extension did not affect the proportions of linearly motile spermatozoa, of membrane integrity or stability nor chromatin integrity, immediately post-thaw. However, high extension clearly affected linear sperm motility following incubation at 38 degrees C for 30 min, sperm viability when assessed by SNARF and, particularly, acrosome integrity of the otherwise viable spermatozoa. Individual sire variation was evident. Fertility was preliminarily evaluated for one of the less affected bulls in a blind field trial. A total of 109 dairy cows were randomly inseminated with 15M or 2M-straws without differences in pregnancy rate between them (47% versus 43%). This similarity in fertility rates, confirmed the in vitro methods used were appropriate for identifying cryosurvival and further suggested the site of sperm deposition was not crucial for the fertility of low-sperm AI-numbers for this particular sire. However, the inter-bull variation seen calls for caution when cryopreserving low concentrations of bull spermatozoa with conventional freezing protocols. (C) 2007 Elsevier Inc. All rights reserved.
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| 8. |
- Harper, Meagan, et al.
(författare)
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A multi-realm perspective on applying potential tipping points to environmental decision-making
- 2023
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Ingår i: Environmental Reviews. - 1181-8700 .- 1208-6053.
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Forskningsöversikt (refereegranskat)abstract
- Ecosystems experiencing pressures are at risk of rapidly transitioning (“tipping”) from one state to another. Identifying and managing these so-called tipping points continue to be a challenge in marine, freshwater, and terrestrial ecosystems, particularly when multiple potentially interacting drivers are present. Knowledge of tipping points, the mechanisms that cause them, and their implications for management practices are evolving, but often in isolation within specific ecological realms. Here, we summarize current knowledge of tipping points in marine, freshwater, and terrestrial realms and provide a multi-realm perspective of the challenges and opportunities for applying this knowledge to ecosystem management. We brought together conservation practitioners and global experts in marine, freshwater, and terrestrial tipping points and identified seven challenges that environmental policymakers and managers contend with including (1) predictability, (2) spatiotemporal scales, (3) interactions, (4) reversibility, (5) socio-ecological context, (6) complexity and heterogeneity, and (7) selecting appropriate action. We highlight opportunities for cross-scalar and cross-realm knowledge production and provide recommendations for enabling the management of tipping points. Although knowledge of tipping points is imperfect, we stress the need to continue working toward incorporating tipping points perspectives in environmental management across all realms.
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| 9. |
- Pena, FJ, et al.
(författare)
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A new and simple method to evaluate early membrane changes in frozen-thawed boar spermatozoa
- 2005
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Ingår i: International Journal of Andrology. - : Wiley-Blackwell. - 0105-6263 .- 1365-2605. ; 28:2, s. 107-114
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Tidskriftsartikel (refereegranskat)abstract
- Detection of early changes in the sperm plasma membrane during cryopreservation is of utmost importance when designing freezing protocols and has previously been studied in the pig species using annexin-V detection of phosphatidylserine translocation. In the present study we designed a new assay to detect these changes in boar spermatozoa, based on the slight increase of sperm membrane permeability occurring during the early stages of cryoinjury, using the combination of three fluorescent probes, SNARF-1, YO-PRO-1 and ethidium homodimer. Four ejaculates from five different boars were frozen-thawed and flow cytometrically (FC) evaluated as paired samples. One of the samples was assayed using the annexin-V/propidium iodide staining and the other sample was evaluated using the new triple staining. Using this combination of probes, four sperm subpopulations were easily detected: viable, with stable membranes (SNARF-1 positive cells), and three with compromised membranes, one of YO-PRO-1+/Eth- cells, one ethidium homodimer+ spermatozoa and, finally spermatozoa stained both with YO-PRO-1 and ethidium homodimer (YO-PRO-1+/Eth+). The latter three categories corresponded to dead spermatozoa, but with different degree of membrane damage, being YO-PRO+/Eth- an earlier stage of membrane destabilization, (manifested by an increase in membrane permeability, while still maintaining membrane integrity) than YO-PRO+/Eth+. A method agreement analysis between both methods was performed revealing good agreement, although the percentage of live cells was 9.44% larger for the triple stain than the annexin-V assay. The new assay stained all sperm sub-populations present in the sample, making it especially suitable for both fluorescence microscopy and flow cytometry, facilitating the exclusion of debris and egg-yolk particles when using FC.
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| 10. |
- Pena, FJ, et al.
(författare)
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Identification of sperm morphometric subpopulations in two different portions of the boar ejaculate and its relation to postthaw quality
- 2005
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Ingår i: Journal of Andrology. - : American Society of Andrology. - 0196-3635 .- 1939-4640. ; 26:6, s. 716-723
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Tidskriftsartikel (refereegranskat)abstract
- A statistical approach using sequentially principal component analysis (PCA), clustering, and discriminant analyses was. developed to identify sperm morphometric subpopulations in well-defined portions of the fresh boar ejaculate. Semen was obtained as 2 portions (the first 10 mL of the sperm-rich fraction and the rest of. the ejaculate, respectively) and frozen using a conventional protocol. Before freezing, an aliquot was Used for computer-assisted. sperm morphometry analysis (ASMA). Postthaw quality was evaluated using computer-assisted sperm analysis (CASA), and an annexin-V/PI assay evaluated sperm membranes. The PCA revealed that 3 variables represented more than 78% of the cumulative variance in sperm subpopulations. The clustering and discriminant analyses, based on 5780 individual spermatozoa, revealed the existence of 4 sperm subpopulations. The relative percentage of these subpopulations Varied between boar and ejaculate portions. Linear regression models based on measured morphometric characteristics could account for up to 36% of the percentage of intact sperm membranes postthaw. The ASMA protocol used in our study was useful to detect subtle morphometric differences between spermatozoa, and the combination of this analysis with a multivariate statistical procedure gave hew information on the biological characteristics of boar ejaculates that is not given by conventional sperm analysis.
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