Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
2.
Evol Appl ; 16(4): 797-813, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37124091

RESUMO

Arctic charr (Salvelinus alpinus) is a niche-market high-value species for Nordic aquaculture. Similar to other salmonids, both anadromous and landlocked populations are encountered. Whole-genome re-sequencing (22X coverage) was performed on two farmed populations of anadromous (Sigerfjord; n = 24) and landlocked (Arctic Superior; n = 24) origin from Norway and Sweden respectively. More than 5 million SNPs were used to study their genetic diversity and to scan for selection signatures. The two populations were clearly distinguished through principal component analysis, with the mean fixation index being ~0.12. Furthermore, the levels of genomic inbreeding estimated from runs of homozygosity were 6.23% and 8.66% for the Norwegian and the Swedish population respectively. Biological processes that could be linked to selection pressure associated primarily with the anadromous background and/or secondarily with domestication were suggested. Overall, our study provided insights regarding the genetic composition of two main strains of farmed Arctic charr from Scandinavia. At the same time, ample genomic resources were produced in the magnitude of millions of SNPs that could assist the transition of Nordic Arctic charr farming in the genomics era.

4.
Animals (Basel) ; 11(10)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34679871

RESUMO

The first artificially fertilized spotted wolffish (Anarhichas minor) eggs hatched in Norway in the mid-1990s as this species was considered by Norwegian authorities to be a top candidate species for cold-water aquaculture in the North Atlantic regions. Previous research conducted in Norway (since 1992) and Canada (since 2000), focused on identifying key biological parameters for spotted wolffish cultivation which led, respectively, to the rapid establishment of a full commercial production line in northern Norway, while Québec (Canada) is witnessing its first privately driven initiative to establish commercial production of spotted wolffish on its territory. The control of reproduction can be viewed as a major requirement to achieve the development of performant strains using genetic selection tools and/or all-year-round production to bring about maximal productivity and synchronization among a given captive population. Although the basic reproduction aspects are more understood and controlled there are still some challenges remaining involving broodstock and upscaling of operations that limit the achievement of a standardized production at the commercial level. Quality of gametes is still considered a major constraint and it can be affected by multiple factors including nutrition, environmental conditions, handling practices, and welfare status. Internal insemination/fertilization and the protracted incubation period are challenging as well as the establishment of a health monitoring program to secure large-scale operations. The profound progress achieved in the control of reproduction, sperm handling, and cryopreservation methods for this species is presented and discussed. In this review, we also go into detail over the full range of up-to-date cultivation practices involving broodstock and identify areas that could benefit from additional research efforts (i.e., broodstock nutrition, health and welfare, scaling-up egg and larval production, genetics, and development of selective breeding programs).

5.
Polymers (Basel) ; 13(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34372158

RESUMO

The aim of our study was to apply a biomimetic approach, inspired by the Ammophila arenaria. This organism possesses a reversible leaf opening and closing mechanism that responds to water and salt stress (hydronastic movement). We adopted a problem-based biomimetic methodology in three stages: (i) two observation studies; (ii) how to abstract and develop a parametric model to simulate the leaf movement; and (iii) experiments with bimetal, a smart material that curls up when heated. We added creases to the bimetal active layer in analogy to the position of bulliform cells. These cells determine the leaf-closing pattern. The experiments demonstrated that creases influence and can change the direction of the bimetal natural movement. Thus, it is possible to replicate the Ammophila arenaria leaf-rolling mechanism in response to temperature variation and solar radiation in the bimetal. In future works, we will be able to propose responsive facade solutions based on these results.

6.
R Soc Open Sci ; 8(3): 201718, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33959336

RESUMO

Cultured Senegalese sole (Solea senegalensis) breeders fail to spawn fertilized eggs. The implantation of large-scale in vitro fertilization protocols, to solve this problem, has been frustrated by low production of poor quality sperm. Cultured females were induced to ovulate with a 5 µg kg-1 single injection of gonadotropin-releasing hormone agonist (GnRHa) and viable eggs (82.6 ± 9.2% fertilization) were stripped 41:57 ± 1:46 h after the injection. Sperm was collected from cultured males, diluted in modified Leibovitz and used fresh to fertilize the eggs. Males were not treated with hormones. A nonlinear regression, an exponential rise to a maximum (R = 0.93, p < 0.0001) described the number of motile spermatozoa required to fertilize a viable egg and 1617 motile spermatozoa were sufficient to fertilize 99 ± 12% (±95% CI) of viable eggs. Similar, spermatozoa egg-1 ratios of 592 ± 611 motile spermatozoa egg-1 were used in large-scale in vitro fertilizations (190 512 ± 38 471 eggs). The sperm from a single male (145 ± 50 µl or 8.0 ± 6.8 × 108 spermatozoa) was used to fertilize the eggs. The mean hatching rate was 70 ± 14% to provide 131 540 ± 34 448 larvae per fertilization. The viability of unfertilized eggs stored at room temperature decreased gradually, and the sooner eggs were fertilized after stripping, the higher the viability of the eggs. The collection of sperm directly into a syringe containing modified Leibovitz significantly increased the percentage of motile spermatozoa (33.4 ± 12.2%) compared with other collection methods. The spz egg-1 ratios for Senegalese sole were at the lower end of ratios required for fish. Senegalese sole have a pair-spawning reproductive behaviour characterized by gamete fertilization in close proximity with no sperm competition. The provision of a large-scale in vitro fertilization protocol (200 µl of sperm per 100 ml of eggs) will enable the industry to operate sustainably and implement breeding programmes to improve production.

7.
PLoS One ; 15(1): e0228307, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31999760

RESUMO

OBJECTIVES: HIV prevalence and incidence are higher among key populations including Men who have Sex with Men (MSM) and transgender women in low and middle income countries, when compared to the general population. Despite World Health Organisation guidelines on the provision of services to key populations recommending an evidence-based, culturally relevant and rights-based approach, uptake of HIV services in many resource-limited and rights-constrained settings remains low. Médecins Sans Frontières (MSF) has been offering health services for MSM and transgender women in Beira, Mozambique since 2014 using a peer-educator driven model, but uptake of services has not been as high as expected. This qualitative study aimed to learn more about these key populations in Beira, their experiences of accessing MSM- and transgender-friendly services and their use of face-to-face and virtual networks, including social media, for engagement with health care. METHODS: In-depth interviews were carried out with MSM and transgender women who were 1) enrolled in, 2) disengaged from or 3) never engaged in MSF's programme. Purposive and snowball sampling were used to recruit the different groups of interviewees. Interviews were conducted in Portuguese, transcribed and translated into English before being coded and manually analysed using a thematic network framework. RESULTS: Nine transgender women and 18 cisgender MSM participated in the study. Interviewees ranged in age from 19 to 47 years, with a median age of 29. Three main themes emerged from the data: perceptions of stigma and discrimination, experiences of the peer-educator driven model and the use of face-to-face and virtual platforms for communication and engagement, including social media. Interviewees reported experiencing stigma and discrimination because of their gender or sexual identity. HIV-related stigma and health-care setting discrimination, including gossip and breach of confidentiality, were also reported. Although the presence of the peer-educators and their outreach activities were appreciated, they had limited visibility and an over-focus on health and HIV. The face-to-face networks of MSM and transgender women were small and fragmented. Virtual networks such as Facebook were mainly used for flirting, dating and informal communication. Most interviewees were at ease using social media and would consider it as a means of engaging with health messaging. CONCLUSIONS: MSM and transgender women have challenges in accessing health services due to being stigmatised because of their gender identity and their sexual behaviour, and often experience stigma at home, in health-care facilities and in their communities. Peer-driven models of engagement were appreciated but have limitations. There is an untapped potential for further expansion and engagement with face-to-face and virtual platforms to reach MSM and transgender women in settings with a high HIV burden, and to provide them with essential information about HIV and their health.


Assuntos
Infecções por HIV/epidemiologia , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Homossexualidade Masculina/psicologia , Educação de Pacientes como Assunto/métodos , Pessoas Transgênero/psicologia , Adulto , Prática Clínica Baseada em Evidências , Feminino , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Moçambique , Prevalência , Pesquisa Qualitativa , Estigma Social , Pessoas Transgênero/estatística & dados numéricos , Adulto Jovem
8.
Theriogenology ; 133: 201-209, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31155035

RESUMO

Males compete pre- and post-mating to fertilize the maximum number of eggs. In polyandry, sperm competition occurs when sperm from two or more males compete to fertilize eggs from a female. Here we review how sperm competition from hatchery origin fish can cause loss of genetic variability in fish populations kept in captivity and in wild populations. In fish hatchery practices, sperm competition occurs in mass spawners that release gametes in tanks, and in artificial fertilizations when pooled semen is used. In mass spawnings sperm competition is difficult to tease apart from pre-mating competition and other post-mating selective mechanisms, whereas, studies focused on the use of pooled semen in different fish species have shown a clear relationship between sperm motility parameters and precedence in fertilization. In both situations, sperm competition will result in a loss of genetic variability that accumulates over generations, but hatchery protocols can be adjusted to mitigate it. Another source of concern regarding sperm competition for hatchery produced fish is the spatial and temporal overlap in spawning with wild individuals, either via aquaculture escapees or purposeful stocking programs. This may result in sperm competition between hatchery origin and wild males and impact natural populations. Our review suggests that in order to give every adult selected as broodstock an equal opportunity to produce offspring in captivity, mass spawning and the use of pooled semen should be limited.


Assuntos
Peixes/fisiologia , Espermatozoides/fisiologia , Animais , Aquicultura , Pesqueiros , Masculino , Reprodução , Motilidade dos Espermatozoides
9.
Theriogenology ; 133: 161-178, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31108371

RESUMO

Artificial reproduction involves collection and handling of gametes in a way that secures their quality and maximizes the fertilization outcome. In addition to initial sperm quality, numerous steps can affect the final result of fertilization, from the sperm collection process until gamete mixing (or co-incubation) when the spermatozoon enters or fuses with the oocyte. In this review, we summarize the whole process of sperm handling, from collection until fertilization for fish, penaeid shrimp, bivalve mollusks and marine mammals. To obtain sperm from captive animals, techniques vary widely across taxa, and include stripping by abdominal massage or testis surgical removal in fish, spermatophore collection in penaeid shrimps, gonadal scarification or temperature shock in bivalve mollusks, and voluntary collection via positive reinforcement in mammals. In most cases, special care is needed to avoid contamination by mucus, seawater, urine, or feces that can either activate sperm motility and/or decrease its quality. We also review techniques and extender solutions used for refrigerated storage of sperm across the aforementioned taxa. Finally, we give an overview of the different protocols for in vivo and in vitro fertilization including activation of sperm motility and methods for gamete co-incubation. The present study provides valuable information regarding breeder management either for animal production or species conservation.


Assuntos
Organismos Aquáticos/fisiologia , Manejo de Espécimes/veterinária , Recuperação Espermática/veterinária , Animais , Crassostrea , Peixes , Inseminação Artificial/veterinária , Masculino , Mamíferos , Penaeidae , Preservação do Sêmen/veterinária , Manejo de Espécimes/métodos
10.
Mar Environ Res ; 147: 90-100, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31023559

RESUMO

Marine food webs are particularly vulnerable to oil spills if keystone species are impacted. To quantify lethal and sublethal toxicity in a key Holarctic forage fish, capelin embryos were exposed to Hibernia crude oil water accommodated fraction (WAF) produced at an oil-to-water ratio of 1:9 (v:v) and chemically-enhanced WAF (CEWAF) produced with the dispersant Corexit™ EC9500A at a dispersant-to-oil ratio of 1:10 (CEWAF H) or 1:50 (CEWAF L). Corexit alone yielded similar embryotoxicity to CEWAF. 10% CEWAF H, with total polycyclic aromatic hydrocarbons of 99.2 µg/L, decreased embryo survival following 10 h of exposure, while continual exposed to 1% CEWAF L decreased hatching and heart rates. Concentrations down to 0.1% CEWAF L increased in a dose-dependent manner the transcript level of cytochrome P4501a1 (cyp1a1) in hatched larvae. These data indicate that embryo-larval survival of capelin is likely at risk if an oil spill coincides in space and time with spawning.


Assuntos
Mallotus (Planta) , Poluição por Petróleo , Petróleo , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Animais , Desenvolvimento Embrionário , Mallotus (Planta)/efeitos dos fármacos , Mallotus (Planta)/embriologia , Mallotus (Planta)/fisiologia , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade
11.
Artigo em Inglês | MEDLINE | ID: mdl-30917981

RESUMO

In sub-Saharan Africa (SSA), gentamicin is commonly used for severe infections in non-intensive-care-unit (ICU) settings, but pharmacokinetic and pharmacodynamic data for this specific population are lacking. We performed a population pharmacokinetic study in an adult Mozambican non-ICU hospital population treated with gentamicin (n = 48) and developed a pharmacokinetic model using nonlinear mixed-effects modeling. Simulations showed that non-ICU patient populations in SSA may be at substantial risk for underexposure to gentamicin during routine once-daily dosing.


Assuntos
Antibacterianos/farmacocinética , Gentamicinas/farmacocinética , Adulto , África Subsaariana , Idoso , Idoso de 80 Anos ou mais , Estado Terminal , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Testes de Sensibilidade Microbiana/métodos , Pessoa de Meia-Idade , Modelos Biológicos , Método de Monte Carlo , Adulto Jovem
12.
Environ Pollut ; 241: 521-528, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29883953

RESUMO

The effects of petroleum aromatic hydrocarbons (PAHs) on the embryonic and larval life stages of teleosts have been extensively examined. However, very little work has been conducted on how spilled oil affects fish sperm and there is no related knowledge concerning oil dispersing agents. The objective of our study was to determine sperm performance of a teleost fish under direct exposure to different concentrations of WAF (water accommodated fraction) and CEWAF (chemically enhanced water accommodated fraction). Capelin sperm motility, swimming behaviour, and sperm fertilization ability were evaluated in a scenario of an oil spill untreated (WAF) and treated (CEWAF) with the dispersant Corexit® EC9500A. Sperm fertilizing ability was lower when exposed to CEWAF concentrations of 16.1 × 103 µg/L total petroleum hydrocarbons and 47.9 µg/L PAH, and when exposed to the dispersant alone. The mechanism responsible for this reduced fertilizing ability is not clear. However, it is not related to the percentage of motile sperm or sperm swimming behaviour, as these were unaffected. WAF did not alter sperm swimming characteristics nor the fertilizing ability. We suggest the dispersant rather than the dispersed oil is responsible for the decrease in the sperm fertilizing ability and hypothesize that the surfactants present in the dispersant affect sperm membrane functionality.


Assuntos
Peixes/fisiologia , Hidrocarbonetos/toxicidade , Lipídeos/toxicidade , Petróleo/toxicidade , Espermatozoides/efeitos dos fármacos , Tensoativos/toxicidade , Animais , Masculino , Poluentes Químicos da Água
13.
J Antimicrob Chemother ; 73(6): 1620-1629, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29522167

RESUMO

Background: In sub-Saharan Africa (SSA), the highly albumin-bound ß-lactam ceftriaxone is frequently used for the empirical treatment of severe bacterial infections. Systemic drug exposure of ß-lactams can be altered in critically ill ICU patients, but pharmacokinetic and pharmacodynamic data for non-ICU SSA populations are lacking. Methods: We performed a population pharmacokinetic study in an adult hospital population in Mozambique, treated with ceftriaxone for presumptive severe bacterial infection from October 2014 to November 2015. Four blood samples per patient were collected for total ceftriaxone (CEFt) and unbound ceftriaxone (CEFu) concentration measurement. We developed a population pharmacokinetic model through non-linear mixed effect analysis and performed simulations for different patient variable, dosing and pharmacodynamic target scenarios. Results: Eighty-eight participants yielded 277 CEFt and 276 CEFu concentrations. The median BMI was 18.9 kg/m2 and the median albumin concentration was 29 g/L. In a one-compartment model with non-linear protein binding, creatinine clearance was positively correlated with CEFu clearance. For microorganisms with an MIC of 1 mg/L, simulations demonstrated that with a 1 g twice-daily regimen and a 2 g once-daily regimen, 95.1% and 74.8% would have a CEFu concentration > MIC during half of the dosing interval (fT>MIC = 50%), respectively, whereas this was only 58.2% and 16.5% for the fT>MIC = 100% target. Conclusions: Severely ill adult non-ICU SSA patients may be at substantial risk for underexposure to CEFu during routine intermittent bolus dosing, especially when their renal function is intact.


Assuntos
Antibacterianos/farmacocinética , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Ceftriaxona/farmacocinética , Ceftriaxona/uso terapêutico , Estado Terminal/epidemiologia , Adolescente , Adulto , África do Norte/epidemiologia , Idoso , Antibacterianos/sangue , Infecções Bacterianas/sangue , Ceftriaxona/sangue , Feminino , Hospitalização , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Modelos Estatísticos , Moçambique/epidemiologia , Estudos Prospectivos , Adulto Jovem
14.
Ecol Evol ; 8(4): 2343-2349, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29468048

RESUMO

Reproduction of external fertilizing vertebrates is typically constrained to either fresh or salt water, not both. For all studied amphibians and fishes, this constraint includes immotile sperm that are activated after ejaculation only by the specific chemistry of the fertilizing medium in which the species evolved (fresh, brackish, or salt water). No amphibians can reproduce in the sea. Although diadromous fishes may migrate between salt and fresh water, they are shackled to their natal environment for spawning in part because of sperm activation. Here, we report for the first time among all documented external fertilizing vertebrates, that in the absence of any external media, sperm are motile at ejaculation in a marine spawning fish (Osmeridae, capelin, Mallotus villosus). To illuminate why, we evaluated sperm behavior at different salinities in M. villosus as well as the related freshwater spawning anadromous rainbow smelt (Osmerus mordax). Surprisingly, sperm performance was superior in fresh water for both species. M. villosus spend their entire life at sea but our results show that their sperm are deactivated by sea water, suggesting a freshwater ancestry. By circumventing constraining water chemistry, we interpret the unique pre-ejaculatory sperm activation in this species as a novel adaptation that enables fertilization in the marine environment. These findings also contribute to understanding the persistence of anadromy, despite great energetic costs to adult fishes.

15.
Clin Infect Dis ; 66(8): 1261-1269, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29112711

RESUMO

Background: In intensive care (ICU) patients, systemic exposure of ß-lactam antibiotics can be altered, and positive clinical outcome is associated with increasing fT > MIC ratios. In sub-Saharan African hospitals, benzylpenicillin (PEN) is frequently used for the empiric treatment of severe pneumococcal infections. Pharmacokinetic data for non-ICU hospitalized populations are lacking. Methods: We performed a population pharmacokinetic (PPK) study in an adult Mozambican hospital population treated intravenously with PEN from October 2014 through November 2015. Four blood samples/patient were collected for total PEN (PENt) and unbound PEN (PENu) concentration measurement. We developed a PPK model through nonlinear mixed-effects analysis and performed simulations for different patient variable, dosing, and pharmacodynamic target scenarios. Results: One hundred twelve participants yielded 387 PENt and 53 PENu concentrations. The median body mass index was 18.3 (range, 10.5-31.3) kg/m2 and the median albumin concentration and creatinine clearance (CrCl) were 29 (range, 12-44) g/L and 80 (range, 3-195) mL/minute, respectively. In a 1-compartment model, CrCl was positively correlated with PENt clearance. For infections with a microorganism with a minimum inhibitory concentration (MIC) of 1 mg/L, simulations demonstrated that with 3 million IU (1.8 g) every 6 hours, 74.1% would have a PENu concentration greater than the MIC during half of the dosing interval (fT > MIC = 50%), whereas this was 24.8% for the fT > MIC = 100% target. For pathogens with an MIC of 0.06 mg/L, these percentages were 98.2% and 72.3%, respectively. Conclusions: Severely ill adult sub-Saharan African patients may be at high risk for underexposure to PENu during routine intermittent bolus dosing, especially when their renal function is intact and when infected with pathogens with intermediate susceptibility.


Assuntos
Antibacterianos/farmacocinética , Penicilina G/farmacocinética , Infecções Pneumocócicas/tratamento farmacológico , Streptococcus pneumoniae/efeitos dos fármacos , Adolescente , Adulto , África Subsaariana , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Simulação por Computador , Cuidados Críticos , Estado Terminal , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Método de Monte Carlo , Infecções Pneumocócicas/microbiologia , Adulto Jovem
16.
PLoS One ; 9(6): e99992, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24941006

RESUMO

Cryopreservation induces injuries to fish spermatozoa that in turn affect sperm quality in terms of fertilization ability, motility, DNA and protein integrity and larval survival. To reduce the loss of sperm quality due to freezing-thawing, it is necessary to improve these procedures. In the present study we investigated the ability of two antifreeze proteins (AFPI and AFPIII) to reduce the loss of quality of sea bream spermatozoa due to cryopreservation. To do so, we compared viability, motility, straight-line velocity and curvilinear velocity of fresh and (AFPs)-cryopreserved spermatozoa. AFPIII addition to cryopreservation medium improved viability, motility and straight-line velocity with respect to DMSO or DMSO plus AFPI. To clarify the molecular mechanism(s) underlying these findings, the protein profile of two different cryopreserved sperm domains, flagella and head plasma membranes, was analysed. The protein profiles differed between fresh and frozen-thawed semen and results of the image analysis demonstrated that, after cryopreservation, out of 270 proteins 12 were decreased and 7 were increased in isolated flagella, and out of 150 proteins 6 showed a significant decrease and 4 showed a significant increase in head membranes. Mass spectrometry analysis identified 6 proteins (4 from isolated flagella and 2 present both in flagella and head plasma membranes) within the protein spots affected by the freezing-thawing procedure. 3 out of 4 proteins from isolated flagella were involved in the sperm bioenergetic system. Our results indicate that the ability of AFPIII to protect sea bream sperm quality can be, at least in part, ascribed to reducing changes in the sperm protein profile occurring during the freezing-thawing procedure. Our results clearly demonstrated that AFPIII addition to cryopreservation medium improved the protection against freezing respect to DMSO or DMSO plus AFPI. In addition we propose specific proteins of spermatozoa as markers related to the procedures of fish sperm cryopreservation.


Assuntos
Proteínas Anticongelantes/farmacologia , Criopreservação , Flagelos/metabolismo , Proteínas de Membrana/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Dourada/metabolismo , Cabeça do Espermatozoide/metabolismo , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Crioprotetores/farmacologia , Eletroforese em Gel Bidimensional , Fertilização/efeitos dos fármacos , Proteínas de Peixes/metabolismo , Masculino , Espectrometria de Massas , Cabeça do Espermatozoide/efeitos dos fármacos , Motilidade dos Espermatozoides/efeitos dos fármacos
17.
Biol Reprod ; 86(2): 59, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22088915

RESUMO

Changes in the plasma membrane lipid composition have been related to a decrease in sperm quality during cryopreservation. Antifreeze proteins (AFPs) have been tested in different species because of their ability to depress the freezing point and their potential interaction with membranes, but controversial effects were reported. In the present study we analyzed separately the lipid composition of two sperm membrane domains, head plasma membrane (HM) and flagellar membrane (FM), after cryopreservation with an extender containing 5% dimethyl sulfoxide (DMSO) either alone or with AFPI or AFPIII (1 µg/ml). We used sperm from a teleost, Sparus aurata, because the lack of acrosome avoids changes of lipid profiles due to capacitation process or acrosomal losses during freezing/thawing. Comparing with the control (cryopreservation with 5% DMSO alone), the addition of AFPIII increased the velocity, linearity of movement, and percentage of viable cells. In addition, freezing with DMSO alone increased the phosphatidyl-serine content as well as the saturated fatty acids and decreased the unsaturated ones (mainly polyunsaturated) both in HM and FM. These changes in the lipid components were highly avoided with the addition of AFPIII. HM had a higher amount of saturated fatty acids than FM and was more affected by cryopreservation without AFPs. The percentage of viable cells was positively correlated with the amount of unsaturated fatty acids in the HM, whereas the motility parameters were positively correlated with both FM and HM amount of unsaturated fatty acids. AFPs, especially AFPIII, seem to have interacted with unsaturated fatty acids, stabilizing the plasma membrane organization during cryopreservation and contributing to improve sperm quality after thawing.


Assuntos
Proteínas Anticongelantes/farmacologia , Membrana Celular/efeitos dos fármacos , Criopreservação/métodos , Crioprotetores/farmacologia , Lipídeos de Membrana/metabolismo , Perciformes/metabolismo , Preservação do Sêmen/métodos , Animais , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Dimetil Sulfóxido/farmacologia , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados/metabolismo , Masculino , Cabeça do Espermatozoide/efeitos dos fármacos , Cabeça do Espermatozoide/ultraestrutura , Cauda do Espermatozoide/efeitos dos fármacos , Cauda do Espermatozoide/ultraestrutura
18.
Theriogenology ; 76(4): 737-44, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21620454

RESUMO

Our previous studies demonstrated that osmolality is the key signal in sperm motility activation in Sparus aurata spermatozoa. In particular, we have proposed that the hyper-osmotic shock triggers water efflux from spermatozoa via aquaporins. This water efflux determines the cell volume reduction and, in turn, the rise in the intracellular concentration of ions. This increase could lead to the activation of adenylyl cyclase and of the cAMP-signaling pathway, causing the phosphorylation of sperm proteins and then the initiation of sperm motility. This study confirms the important role of sea bream AQPs (Aqp1a and Aqp10b) in the beginning of sperm motility. In fact, when these proteins are inhibited by HgCl(2), the phosphorylation of some proteins (174 kDa protein of head; 147, 97 and 33 kDa proteins of flagella), following the hyper-osmotic shock, was inhibited (totally or partially). However, our results also suggest that more than one transduction pathways could be activated when sea bream spermatozoa were ejaculated in seawater, since numerous proteins showed an HgCl(2)(AQPs)-independent phosphorylation state after motility activation. The role played by each different signal transduction pathways need to be clarified.


Assuntos
Adenilil Ciclases/metabolismo , Aquaporinas/antagonistas & inibidores , Dourada/metabolismo , Motilidade dos Espermatozoides/fisiologia , Espermatozoides/metabolismo , Animais , Aquaporinas/metabolismo , Flagelos/efeitos dos fármacos , Flagelos/fisiologia , Masculino , Cloreto de Mercúrio/farmacologia , Concentração Osmolar , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Motilidade dos Espermatozoides/efeitos dos fármacos , Gravação em Vídeo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA