Bibliografías temáticas / Sperm midpiece

Índice

Artículos de revistas
Tesis
Capítulos de libros

Literatura académica sobre el tema "Sperm midpiece"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 1 de febrero de 2022

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros

Elija tipo de fuente:

Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Sperm midpiece".

Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.

También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.

Artículos de revistas sobre el tema "Sperm midpiece"

Comizzoli, P., D. Wildt y B. Pukazhenthi. "354 POOR EMBRYO DEVELOPMENT AFTER ICSI WITH DOMESTIC CAT TESTICULAR SPERM IS OVERCOME BY CENTROSOME AND MIDPIECE REPLACEMENT". Reproduction, Fertility and Development 18, n.º 2 (2006): 284. http://dx.doi.org/10.1071/rdv18n2ab354.

Texto completo

Resumen

Testicular sperm from the cat can be used via intracytoplasmic sperm injections (ICSI) to produce embryos in vitro, but the proportion of morulae and blastocysts is less than that obtained using ejaculated sperm. Compromised embryo development has been linked to the inability of the cat testicular sperm centrosome to form a normal sperm aster during the first cell cycle post-ICSI. The aim of the present study was to improve embryo development after ICSI with a testicular spermatozoon by centrosome/midpiece replacement from an ejaculated spermatozoon. Sperm suspensions used for ICSI (fresh testicular sperm from one adult testis vs. frozen-thawed sperm from one ejaculate in each replicate; four replicates) were sonicated for 3 s at setting 3 using a 60 Sonic Dismembrator (Fisher Scientific, Pittsburgh, PA, USA) to separate heads from centrosome/midpieces. Control immunostaining with monoclonal centrin antibodies revealed that centrosomes were attached to midpieces and were separated from sperm heads after sonication. A single sperm head (testicular, Th; ejaculated, Eh) was carefully positioned proximal to a single centrosome/midpiece (testicular, Tc; ejaculated, Ec) before injection into an oocyte with a visible polar body (in each replicate, n = 18 oocytes injected with each ThEc, EhEc, EhTc, or ThTc combination; four replicates). Injected oocytes then were activated with 7% ethanol and cultured in vitro in Ham's F10 (38.5�C, 5% CO2 in air). Percentages of first cleavages were recorded from 20 to 32 h post-activation (hpa). Nuclear status of uncleaved oocytes was evaluated at 48 hpa, and embryo development was assessed after 7 days of in vitro culture. Values were expressed as mean � standard deviation and analyzed by ANOVA. None of the uncleaved oocytes were activated. Percentages of cleaved oocytes (relative to the total number of injected oocytes) were not different (range, 61-65%; P > 0.05) among combinations of sperm heads and centrosome/midpieces. The mean times of the first cleavage, however, were earlier (P < 0.05) after combinations with ejaculated centrosome/midpieces (ThEc, 25.1 � 1.1 h; EhEc, 25.0 � 0.9 h) than with testicular centrosome/midpieces (EhTc, 29.2 � 0.8 h; ThTc, 29.3 � 1.2 h). Percentages of morulae produced were higher (P < 0.05) after combinations with ejaculated centrosome/midpieces (ThEc, 15.3 � 2.7%; EhEc, 16.7 � 2.1%) than with testicular centrosome/midpieces (EhTc, 8.3 � 3.1%; ThTc, 6.9 � 2.2%). Likewise, percentages of blastocysts were higher (P < 0.05) after combinations with ejaculated centrosome/midpieces (ThEc, 12.5 � 3.0%; EhEc, 13.9 � 2.8%) than with testicular centrosome/midpieces (EhTc, 5.6 � 3.3%; ThTc, 6.9 � 2.9%). These results demonstrated that: (1) kinetics of the first cell cycle and the success of embryonic development were determined by centrosome/midpiece source; and (2) poor developmental potential of domestic cat testicular sperm could be circumvented by centrosome/midpiece replacement from an ejaculated spermatozoon.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Vladić, Tomislav y Erik Petersson. "Artificially selected human sperm morphology after swim-up processing". Canadian Journal of Zoology 90, n.º 10 (octubre de 2012): 1207–14. http://dx.doi.org/10.1139/z2012-088.

Texto completo

Resumen

The swim-up technique is a clinical practice used to select highly motile sperm cells from patient ejaculates to use in assisted fertilization. The aim of this study was to investigate whether the length of different sperm-cell components is related to gamete function. Thus, we explored whether swim-up technique selects for longer sperm cells than mean sperm cells from unprocessed ejaculates. Sperm midpiece, tail endpiece, and total length were measured before and after the swim-up selection by means of contrast-phase and electron microscopy. Correlations between sperm dimensions, sperm motility, and sperm concentration were also investigated. Swim-up selected cells with longer midpiece compared with the unprocessed fractions (5.8 μm (CI 5.52–6.16 μm) vs. 5.3 μm (CI 4.97–5.61 μm), p < 0.05) and shorter tail endpiece (7.8 μm (CI 7.11–8.44 μm) vs. 8.5 μm (CI 7.81–9.14 μm), p < 0.05 after meta-analysis), whereas no effect of swim-up selection was detected on the total sperm cell length. Individuals producing high sperm concentrations had longer sperm midpiece than had men producing lower sperm concentrations. It is concluded that short sperm flagellar tips with long midpieces may be used as biomarkers in infertility therapy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Knief, Ulrich, Wolfgang Forstmeier, Bart Kempenaers y Jochen B. W. Wolf. "A sex chromosome inversion is associated with copy number variation of mitochondrial DNA in zebra finch sperm". Royal Society Open Science 8, n.º 9 (septiembre de 2021): 211025. http://dx.doi.org/10.1098/rsos.211025.

Texto completo

Resumen

The propulsion of sperm cells via movement of the flagellum is of vital importance for successful fertilization. While the exact mechanism of energy production for this movement varies between species, in avian species energy is thought to come predominantly from the mitochondria located in the sperm midpiece. Larger midpieces may contain more mitochondria, which should enhance the energetic capacity and possibly promote mobility. Due to an inversion polymorphism on their sex chromosome TguZ , zebra finches ( Taeniopygia guttata castanotis ) exhibit large within-species variation in sperm midpiece length, and those sperm with the longest midpieces swim the fastest. Here, we test through quantitative real-time PCR in zebra finch ejaculates whether the inversion genotype has an effect on the copy number of mitochondrial DNA (mtDNA). We find that zebra finches carrying the derived allele (correlated with longer sperm midpieces) have more copies of the mtDNA in their ejaculates than those homozygous for the ancestral allele (shorter midpieces). We suggest downstream effects of mtDNA copy number variation on the rate of adenosine triphosphate production, which in turn may influence sperm swimming speed and fertilization success. Central components of gamete energy metabolism may thus be the proximate cause for a fitness-relevant genetic polymorphism, stabilizing a megabase-scale inversion at an intermediate allele frequency in the wild.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tilney, L. G. y S. Inoué. "Flagellar gyration and midpiece rotation during extension of the acrosomal process of Thyone sperm: how and why this occurs." Journal of Cell Biology 104, n.º 3 (1 de marzo de 1987): 407–15. http://dx.doi.org/10.1083/jcb.104.3.407.

Texto completo

Resumen

The midpiece of Thyone sperm contains a large mitochondrion and a centriolar pair. Associated with one of the pair, i.e., the basal body of the flagellum, are satellite structures which apparently anchor the flagellar axoneme to the mitochondrion and to the plasma membrane covering the midpiece. Immediately before and as the acrosomal process elongates, the flagellum and the midpiece begin to rotate at 1-2 rotations per second even though the head of the sperm, by being firmly attached on its lateral surfaces to the coverslip, does not rotate at all. This rotation is not observed in the absence of flagellar beating whose frequency is much greater than that of its gyration. To understand how the midpiece rotates relative to the sperm head, it is first necessary to realize that in Thyone the flagellar axoneme projects at an acute angle to the principal axis of the sperm and is bent towards one side of this axis. Thus movement of the flagellum induces the sperm to tumble or yaw in solution. If the head is stuck, the midpiece will rotate because all that connects the sperm head to the midpiece is the plasma membrane, a liquid-like layer. A finger-like projection extends from the proximal centriole into an indentation in the basal end of the nucleus. In contrast to the asymmetry of the flagellum, this indentation is situated exactly on the principal axis of the sperm and, along with the finger-like projection, acts as a biological bearing to maintain the orderly rotation of the midpiece. The biological purpose of flagellar gyration during fertilization is discussed.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Bennison, Clair, Nicola Hemmings, Lola Brookes, Jon Slate y Tim Birkhead. "Sperm morphology, adenosine triphosphate (ATP) concentration and swimming velocity: unexpected relationships in a passerine bird". Proceedings of the Royal Society B: Biological Sciences 283, n.º 1837 (31 de agosto de 2016): 20161558. http://dx.doi.org/10.1098/rspb.2016.1558.

Texto completo

Resumen

The relationship between sperm energetics and sperm function is poorly known, but is central to our understanding of the evolution of sperm traits. The aim of this study was to examine how sperm morphology and ATP content affect sperm swimming velocity in the zebra finch Taeniopygia guttata . We exploited the high inter-male variation in this species and created extra experimental power by increasing the number of individuals with very long or short sperm through artificial selection. We found a pronounced quadratic relationship between total sperm length and swimming velocity, with velocity increasing with length up to a point, but declining in the very longest sperm. We also found an unexpected negative association between midpiece length and ATP content: sperm with a short midpiece generally contained the highest concentration of ATP. Low intracellular ATP is therefore unlikely to explain reduced swimming velocity among the very longest sperm (which tend to have a shorter midpiece).

Los estilos APA, Harvard, Vancouver, ISO, etc.

Malo, Aurelio F., Montserrat Gomendio, Julian Garde, Barbara Lang-Lenton, Ana J. Soler y Eduardo R. S. Roldan. "Sperm design and sperm function". Biology Letters 2, n.º 2 (23 de febrero de 2006): 246–49. http://dx.doi.org/10.1098/rsbl.2006.0449.

Texto completo

Resumen

Spermatozoa vary enormously in their form and dimensions, both between and within species, yet how this variation translates into fertilizing efficiency is not known. Sperm swimming velocity is a key determinant of male fertilization success, but previous efforts to identity which sperm phenotypic traits are associated with swimming velocity have been unsuccessful. Here, we examine the relationship between the size of several sperm components and sperm swimming velocity in natural populations of red deer ( Cervus elaphus hispanicus ) where selective pressures to enhance male reproductive success are expected to be strong. Our results show that there is little within-male and considerable between-male variation in sperm dimensions. Spermatozoa with longer midpieces swim more slowly, a finding which does not support the hypothesis that the size of the midpiece determines the amount of energy which is translated into swimming speed. In contrast, spermatozoa with elongated heads, and those in which the relative length of the rest of the flagellum is longer, swim faster. Thus, the hydrodynamic shape of the head and the forces generated by the relative size of the rest of the flagellum seem to be the key determinants of sperm swimming velocity.

Los estilos APA, Harvard, Vancouver, ISO, etc.

A..S..Abood, S. A. Hatif And. "Rams Infertility and Sperms Mitochondrial Genome Defect". Al-Qadisiyah Journal of Veterinary Medicine Sciences 10, n.º 2 (28 de diciembre de 2011): 55. http://dx.doi.org/10.29079/vol10iss2art154.

Texto completo

Resumen

This study was included a collection of 24 semen samples from healthy rams in Baghdad Province, performed in Baghdad- college of veterinary medicine.S perms stained with fluorescent dye ( ethidium bromide ) and subjected to fluorescent microscopical examination used by UV- light to visualize the defect in the mitochondrial sheath covered the midpiece. The results give the abnormalities of mitochondrial midpiece (mt sheat), the sperms appeared in 6 types of defect, included a mixed defect in the same sample. The defect included 5 ( 20.8%) cases interrupted distribution of mt genome, 4 (16.6%) narrow, 10 (41.6%) thickness , 8 (33.3%)irregular , 7(29.16%) short and 2(8.3%) absent of midpiece . The aim of this study, determination the defect of a mitochondrial sheath of midpiece, inactivity, motility, low quality of sperm and the role of infertility in ram.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Firman, Renée C. y Leigh W. Simmons. "Sperm midpiece length predicts sperm swimming velocity in house mice". Biology Letters 6, n.º 4 (10 de febrero de 2010): 513–16. http://dx.doi.org/10.1098/rsbl.2009.1027.

Texto completo

Resumen

Evolutionary biologists have argued that there should be a positive relationship between sperm size and sperm velocity, and that these traits influence a male's sperm competitiveness. However, comparative analyses investigating the evolutionary associations between sperm competition risk and sperm morphology have reported inconsistent patterns of association, and in vitro sperm competition experiments have further confused the issue; in some species, males with longer sperm achieve more competitive fertilization, while in other species males with shorter sperm have greater sperm competitiveness. Few investigations have attempted to address this problem. Here, we investigated the relationship between sperm morphology and sperm velocity in house mice ( Mus domesticus ). We conducted in vitro sperm velocity assays on males from established selection lines, and found that sperm midpiece size was the only phenotypic predictor of sperm swimming velocity.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Cramer, Emily R. A., Eduardo Garcia-del-Rey, Lars Erik Johannessen, Terje Laskemoen, Gunnhild Marthinsen, Arild Johnsen y Jan T. Lifjeld. "Longer Sperm Swim More Slowly in the Canary Islands Chiffchaff". Cells 10, n.º 6 (31 de mayo de 2021): 1358. http://dx.doi.org/10.3390/cells10061358.

Texto completo

Resumen

Sperm swimming performance affects male fertilization success, particularly in species with high sperm competition. Understanding how sperm morphology impacts swimming performance is therefore important. Sperm swimming speed is hypothesized to increase with total sperm length, relative flagellum length (with the flagellum generating forward thrust), and relative midpiece length (as the midpiece contains the mitochondria). We tested these hypotheses and tested for divergence in sperm traits in five island populations of Canary Islands chiffchaff (Phylloscopus canariensis). We confirmed incipient mitochondrial DNA differentiation between Gran Canaria and the other islands. Sperm swimming speed correlated negatively with total sperm length, did not correlate with relative flagellum length, and correlated negatively with relative midpiece length (for Gran Canaria only). The proportion of motile cells increased with relative flagellum length on Gran Canaria only. Sperm morphology was similar across islands. We thus add to a growing number of studies on passerine birds that do not support sperm morphology–swimming speed hypotheses. We suggest that the swimming mechanics of passerine sperm are sufficiently different from mammalian sperm that predictions from mammalian hydrodynamic models should no longer be applied for this taxon. While both sperm morphology and sperm swimming speed are likely under selection in passerines, the relationship between them requires further elucidation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Lawrence, M., G. Mastromonaco, K. Goodrowe, R. M. Santymire, W. Waddell y A. I. Schulte-Hostedde. "The effects of inbreeding on sperm morphometry of captive-bred endangered mammals". Canadian Journal of Zoology 95, n.º 8 (agosto de 2017): 599–606. http://dx.doi.org/10.1139/cjz-2016-0291.

Texto completo

Resumen

Captive breeding is used for the conservation of endangered species, but inbreeding can result when a small number of founders are used to establish populations. Inbreeding can reduce the proportion of normal sperm in an ejaculate, but may also have effects on sperm size and shape (morphometry). We investigated the effects of inbreeding on sperm morphometry of black-footed ferrets (Mustela nigripes (Audubon and Bachman, 1851)) and red wolves (Canis rufus Audubon and Bachman, 1851) from captive breeding programs to determine if more inbred males produced sperm of poor quality (bulky head, small midpiece, short tail). We measured sperm head length, head width, midpiece length, midpiece width, and tail length on 10 sperm from each male of both species. A negative relationship between variation in sperm tail length and inbreeding coefficient (f) was found in black-footed ferret, suggesting that more inbred individuals will have reduced genetic and phenotypic variation. Analyses indicated a negative relationship between sperm head width and f and a positive relationship between sperm tail length and f in red wolf, suggesting that more inbred male red wolves could have faster sperm. These results indicate that inbreeding affects functionally important aspects of sperm morphometry, but that these effects may not be entirely negative.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Tesis sobre el tema "Sperm midpiece"

Maree, Liana. "Sperm mitochondria: Species specificity and relationships to sperm morphometric features and sperm function in selected mammalian species". Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1728_1363788268.

Texto completo

Resumen

Numerous studies on mammalian spermatozoa have reported large variations in the dimensions of the main sperm structural components, namely the head, midpiece and flagellum. These variations in sperm architecture are believed to be adaptations for functioning of spermatozoa in complex environments outside the male reproductive system. The midpiece of the mammalian
permatozoon contains a varied number of mitochondria, but the reason for the marked difference in the size and structure of this sperm component is not clear. This study
confirmed the variations in the sperm morphometry of seven selected mammalian species and revealed unique features of the sperm midpiece and sperm mitochondria of these seven species. Evaluation of several sperm kinematic parameters revealed the unique swimming characteristics of the different spermatozoa. The importance of using standardized motility
parameters was highlighted as well as the assessment of different subpopulations of spermatozoa in order to produce more reliable and comparable data. Investigating the role of sperm mitochondria in human sperm
metabolism indicated that these organelles are related to sperm function in terms of sperm motility. Furthermore, it was suggested that glycolysis and mitochondrial respiration are linked processes and that both are important for the maintenance of human sperm motility. By optimizing and employing standardized experimental procedures and analysis techniques, this study was
able to confirm the species specificity of almost all the sperm parameters evaluated, while also elucidating the phylogenetic relatedness of the non-human primate species. In conclusion, the present study has confirmed that the various midpiece morphometry parameters are related to the remaining sperm morphometry parameters as well as to the sperm kinematic parameters.
These proposed associations between the various sperm parameters were used to explain the sperm velocity of two hypothetical and morphologically different sperm structures. Therefore, the results of the current study support the idea of co-evolution between sperm components in mammalian spermatozoa and propose that the midpiece morphometry parameters that are selected for in these spermatozoa are midpiece volume, total number of mitochondrial gyres, thickness of the mitochondrial sheath and mitochondrial height.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Capítulos de libros sobre el tema "Sperm midpiece"

"Conservation, Ecology, and Management of Catfish: The Second International Symposium". En Conservation, Ecology, and Management of Catfish: The Second International Symposium, editado por JOSEPH N. STOECKEL y RICHARD J. NEVES. American Fisheries Society, 2011. http://dx.doi.org/10.47886/9781934874257.ch22.

Texto completo

Resumen

Abstract.—Captive spawning is a strategy to bolster populations of rare madtoms Noturus spp., but very little is known regarding their reproductive development in captivity. The primary goal of this research was to develop methods to stimulate gonadal maturation of captive madtoms. We used the nonimperiled margined madtom N. insignis as a model species to investigate the effects of photothermal regimes on gonadal development and reproductive hormones. We also evaluated testicular development of madtoms injected with common carp Cyprinus carpio pituitary extract (CPE). Changing photoperiod, but not temperature, was required to induce oocyte maturation in a high percentage of captive female margined madtoms. Gonadosomatic index (GSI) values of captive females were similar to those of gravid wild ﬁsh collected during or just prior to the spawning season with the time to maturation of oocytes shortened by as much as 3 months. Many of the captive males developed large, square-shaped heads with swollen cephalic epaxial muscles as spawning conditions approached, but their GSI values were not different from those of ﬁsh sampled at other times of the year. Injections of CPE increased the GSI value and vascularization of testes but not the number of spermatozoa. In general, sperm production in mature male madtoms was enigmatic in captive and wild ﬁsh, inasmuch as motile sperm were observed only once. The heads of margined madtom spermatozoa are slightly ovate (4.3 0.2 μm long and 3.6 0.2 μm wide). The tails are centrally attached to the head and are more than 112.5 μm long. A pronounced, collar-like midpiece encircles the posterior portion of the head and anterior portion of the tail. Plasma testosterone concentrations in males peaked just prior to the spawning season at 6.5 ng/mL, but levels were not correlated with male GSI values. Plasma 17β-estradiol levels in females peaked just prior to the spawning season at 15 ng/mL and were correlated with gonadosomatic values.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ofrecemos descuentos en todos los planes premium para autores cuyas obras están incluidas en selecciones literarias temáticas. ¡Contáctenos para obtener un código promocional único!