Search results for "sperm"
showing 10 items of 658 documents
Interstitial Telomeric-like Repeats (ITR) in Seed Plants as Assessed by Molecular Cytogenetic Techniques: A Review.
2021
The discovery of telomeric repeats in interstitial regions of plant chromosomes (ITRs) through molecular cytogenetic techniques was achieved several decades ago. However, the information is scattered and has not been critically evaluated from an evolutionary perspective. Based on the analysis of currently available data, it is shown that ITRs are widespread in major evolutionary lineages sampled. However, their presence has been detected in only 45.6% of the analysed families, 26.7% of the sampled genera, and in 23.8% of the studied species. The number of ITR sites greatly varies among congeneric species and higher taxonomic units, and range from one to 72 signals. ITR signals mostly occurs…
Profound Transcriptomic Differences Found between Sperm Samples from Sperm Donors vs. Patients Undergoing Assisted Reproduction Techniques Tends to D…
2010
Background Although spermatozoa delivers its RNA to oocytes at fertilization, its biological role is not well characterized. Our purpose was to identify the genes differentially and exclusively expressed in sperm samples both before and after the swim-up process in control donors and infertile males with the purpose to identify their functional significance in male fertility. Materials and methods This was a nested case-control study. Ten sperm samples were obtained from infertile patients [n=5 (two aliquots each from five samples; one before the swim-up process and one after)] and donors [n=5 (two aliquots from five samples, one before the swim-up process and one after)]. Oligonucleotide m…
Lierojen parittelumenestyksen yhteys sää- ja ympäristöoloihin, yksilötiheyteen ja yksilön kokoon
2011
Yksilön kelpoisuus riippuu jälkeläistuotosta, ja parittelumenestys on yksi jälkeläistuoton avaintekijöistä. Monien eläinlajiryhmien lisääntymistä on tutkittu laajasti sekä laboratorio-oloissa että luonnossa, mutta lierojen lisääntymismenestykseen vaikuttavia tekijöitä luonnonpopulaatioissa ei vielä juurikaan tunneta. Tämän tutkimuksen tavoitteena oli selvittää, miten kahden ekologialtaan erilaisen lierolajin parittelumenestys riippuu ympäristöoloista, yksilötiheydestä ja yksilön koosta. Tutkimuksessa käytettiin tietoja lieronäytteistä, jotka oli kerätty syksyinä 2004 ja 2005 viljelymailta eri puolilta Suomea. Spermatoforien esiintymistä yksilöillä käytettiin indikaattorina näytteenottoa ede…
Temperature effects explain continental scale distribution of cyanobacterial toxins
2018
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect…
Lipo-Sarcoma Multifocale del Funicolo Spermatico: indicazioni al trattamento chirurgico e descrizione di un caso con follow-up a lungo termine.
2006
Poster per X Riunione S.R.S.-S.I.A.. Messina (Milazzo), 28-29 Aprile 2006
Desarrollo de modelos predictivos matemáticos de éxito en tratamientos de reproducción asistida para pacientes con azoospermia no obstructiva
2021
Entre las formas más graves de infertilidad de origen masculino se encuentra la azoospermia no obstructiva (ANO), que es la ausencia de espermatozoides en el semen eyaculado después de centrifugación como consecuencia del fallo testicular al inicio o durante la espermatogénesis. Las opciones de tratamiento para pacientes con ANO y deseo de paternidad son la recuperación espermática mediante biopsia testicular (TESE o micro-TESE) y posterior ICSI, la utilización de semen de donante o bien la adopción. Para evitar procedimientos innecesarios y poder ofrecer un consejo adecuado a las parejas afectas, distintos autores han intentado determinar qué pacientes son mejores candidatos a biopsia test…
Do highly ornamented and less parasitized males have high quality sperm? - an experimental test for parasite-induced reproductive trade-offs in Europ…
2014
Parasites take their resources from hosts and thus directly reduce available resources for hosts’ own body functions, such as growth and reproduction. Furthermore, parasite infections cause significant indirect costs to their hosts in terms of increased investments on immune defense. In this study, we investigated the impact of parasite infection on the sperm quality and expression of secondary sexual ornamentation (saturation of the red abdominal colouration and number of breeding tubercles) in the Eurasian minnow (Phoxinus phoxinus). We exposed minnows to a high and low dose of common nonspecific fish ectoparasite, the glochidia larvae of duck mussel (Anodonta anatina) and tested whether …
Data from: Postcopulatory sexual selection generates speciation phenotypes in Drosophila
2013
Background: Identifying traits that reproductively isolate species, and the selective forces underlying their divergence, is a central goal of evolutionary biology and speciation research. There is growing recognition that postcopulatory sexual selection, which can drive rapid diversification of interacting ejaculate and female reproductive tract traits that mediate sperm competition, may be an engine of speciation. Conspecific sperm precedence (CSP) is a taxonomically widespread form of reproductive isolation, but the selective causes and divergent traits responsible for CSP are poorly understood. Results: To test the hypothesis that postcopulatory sexual selection can generate reproductiv…
Data from: No evidence for prezygotic postcopulatory avoidance of kin despite high inbreeding depression
2018
Offspring resulting from mating among close relatives can suffer from impaired fitness through the expression of recessive alleles with deleterious effects. Post-copulatory sperm selection (a pre-zygotic mechanism of cryptic female choice) has been suggested to be an effective way to avoid inbreeding. To investigate whether post-copulatory female choice allows avoiding fertilization by close kin, we performed artificial inseminations in a promiscuous bird, the houbara bustard (Chlamydotis undulata undulata). Females were inseminated with a mix of sperm from triads of males, each constituted of a male genetically unrelated to the female, a first cousin, and a half-sibling. When counting the …
Data from: Strategic adjustments in sperm production within and between two island populations of house mice
2013
Sperm production is physiologically costly. Consequently, males are expected to be prudent in their sperm production, and tailor their expenditure according to prevailing social conditions. Differences in sperm production have been found across island populations of house mice that differ in the level of selection from sperm competition. Here, we determined the extent to which these differences represent phenotypic plasticity and/or population divergence in sperm production. We sourced individuals from two populations at the extreme levels of sperm competition, and raised them under common-garden conditions while manipulating the social experience of developing males. Males from the high-sp…