Maria Alexandra Barreto Amaral
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Data da última atualização
»Last update
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02/12/2013 |
Dados pessoais (Personal data)
Nome completo
Full name |
Maria Alexandra Barreto Amaral |
Nome em citações bibliográficas
Quoting name |
Alexandra Amaral |
Domínio científico de atuação
Scientific domain |
Ciências Médicas-Biotecnologia Médica. Ciências Naturais-Ciências Biológicas.
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Endereço profissional
Professional address |
Universidade de Coimbra Centro de Neurociências de Coimbra Centro de Neurociências e Biologia Celular, Universidade de Coimbra, Largo Marquês de Pombal Coimbra 3004-517 Coimbra Portugal Telefone: (+351)239855760 Correio electrónico: mabamaral@uc.pt Homepage: http://www.cnbc.pt/ |
Sexo
Gender |
Feminino»Female |
Graus Académicos
(Academic Degrees)
2003-2010 |
Doutoramento Phd |
Biologia Celular.
Universidade de Coimbra,
Portugal.
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1997-2002 |
Licenciatura Licentiate degree |
Biologia
(4 anos » years)
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Universidade de Coimbra,
Portugal.
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Formação complementar ( studies)
2009-2009 |
Curso de curta duração Short course |
Frontiers in Reproduction.
Marine Biological Laboratory,
Estados Unidos.
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2002-2003 |
Outros Others |
Mestrado em Biologia Celular. Universidade de Coimbra,
Portugal.
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2000-2002 |
Outros Others |
Realização de trabalhos laboratoriais na área da Biotecnologia Vegetal. Universidade de Coimbra,
Portugal.
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Vínculos profissionais
(Professional Positions)
Mar/2010-Actual |
Outra Situação |
Centro de Neurociências e Biologia Celular |
Mar/2010-Actual |
Outra Situação |
Centro de Neurociências e Biologia Celular |
Out/2003-Actual |
Outra Situação |
Clinimer (Assisted Reproduction Clinic) |
Jul/2009-Nov/2009 |
Técnico Superior Principal |
Centro de Neurociências e Biologia Celular |
Out/2002-Out/2003 |
Assistente de Investigação |
Atividades de Investigação e Desenvolvimento (Research and Development activities)
Centro de Neurociências e Biologia Celular |
Centro de Neurociências e Biologia Celular |
Estágios realizados (Traineeships)
Centro de Neurociências e Biologia Celular |
Estágios realizados»Traineeships: - "Biologia Celular e Molecular de espermatozóides", Faculdade de Medicina da Universidade de Birmingham
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Linhas de Investigação (Research fields)
1. |
Human sperm mitochondrial function |
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Objectivos»Goals:
To understand the role of mitochondria and mitochondrial DNA (mtDNA) in human sperm function.
Analysis of distinct mitochondrial parameters in distinct quality sperm samples: mtDNA copy number; mitochondrial proteins
expression (POLG, TFAM, COXI, COVIc); POLG polymorphisms; mitochondrial membrane potential..
Domínio Científico:
Ciências Médicas / Área Científica:
Biotecnologia Médica.
Domínio Científico:
Ciências Naturais / Área Científica:
Ciências Biológicas.
Objectivos socio-económicos:
Promoção geral dos conhecimentos; Protecção e promoção da saúde humana. Palavras-chave:
Human sperm; Mitochondria; Mitochondrial DNA; Mitochondrial proteins; Mitochondrial membrane potential; Male infertility.
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2. |
The sperm energy metabolism debate: glycolysis versus mitochondrial oxidative phoshorylation |
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Objectivos»Goals:
To determine what is the nature of the ATP that fuels sperm motility/capacitation/acrosome reaction by using a long-term culture
approach. .
Domínio Científico:
Ciências Médicas / Área Científica:
Biotecnologia Médica.
Domínio Científico:
Ciências Naturais / Área Científica:
Ciências Biológicas.
Objectivos socio-económicos:
Promoção geral dos conhecimentos; Protecção e promoção da saúde humana. Palavras-chave:
Human sperm; oxidative phosphorylation; Glycolysis; metabolism; in vitro culture.
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3. |
The significance of distinct sperm functional parameters in predicting fertilization ability |
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Objectivos»Goals:
To analyse distinct sperm functional parameters and evaluate their clinical value.
Comparison between sperm samples form fertile donors and infertile patients for the following parameters: plasma membrane
integrity; mitochondrial membrane potential; chromatin integrity; acrosome status; capacitation status. Assessment of correlations
with ART (assisted reproduction techniques) results.
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Domínio Científico:
Ciências Médicas / Área Científica:
Biotecnologia Médica.
Domínio Científico:
Ciências Naturais / Área Científica:
Ciências Biológicas.
Objectivos socio-económicos:
Promoção geral dos conhecimentos; Protecção e promoção da saúde humana. Palavras-chave:
Human sperm function; Fertilization ability; Chromatin integrity; Acrosome; Capacitation; Mitochondrial funtion.
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4. |
Development of novel techniques to evaluate human fertilisation failures at the cellular level |
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Objectivos»Goals:
To sequentially and reliably apply both tubulin immunocytochemistry (ICC) and fluorescence in
situ hybridization (FISH) to human fertilization failures, thus providing a tool for a multiple analysis of arrest..
Domínio Científico:
Ciências Médicas / Área Científica:
Biotecnologia Médica.
Domínio Científico:
Ciências Naturais / Área Científica:
Ciências Biológicas.
Objectivos socio-económicos:
Promoção geral dos conhecimentos; Protecção e promoção da saúde humana. Palavras-chave:
Human fertilization failures; microtubules; Immunocytochemistry; FISH; human oocyte.
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Projetos de Investigação (Research projects)
Participação como Doutorando Participation as Phd student |
2006-2008 Sperm function: What makes a good spermatozoon? A trans-specific perspective |
Referência do projeto»Project reference: III/BIO/50/2005. Financiador(es)»Funding:
Universidade de Coimbra.
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2005-2008 Caracterização funcional de espermatozóides equinos. Avaliação molecular da fertilidade de garanhões. -Functional characterization of equine sperm. A molecular evaluation of stallion fertility |
Referência do projeto»Project reference: POCTI/CVT/49102/2002. Financiador(es)»Funding:
Fundação para a Ciência e a Tecnologia.
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2002-2005 Dinâmica intracelular e bionergética mitocondrial durante espermiogénese e actividade de espermatozóides: Implicações para
a fertilidade humana -Mitochondrial bioenergetics and membrane dynamics during spermiogenesis and sperm function: implications for human fertility
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Referência do projeto»Project reference: POCTI/ESP/38049/2001. Financiador(es)»Funding:
Fundação para a Ciência e a Tecnologia.
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Outro Tipo de Participação Other kind of participation |
2006-2009 Implementation of a National Facility for DNA Microarrays: Phase II |
Referência do projeto»Project reference: PTDC/BIA-BCM/64745/2006. Financiador(es)»Funding:
Fundação para a Ciência e a Tecnologia.
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Línguas (Languages)
Compreende Understandig |
Inglês (Bem), Português (Bem), Francês (Bem), Espanhol (Bem), Catalão (Bem). |
Fala Speaking |
Inglês (Bem), Português (Bem), Francês (Bem), Espanhol (Bem), Catalão (Pouco). |
Lê Reading |
Inglês (Bem), Português (Bem), Francês (Bem), Espanhol (Bem), Catalão (Bem). |
Escreve Writing |
Inglês (Bem), Português (Bem), Francês (Bem), Espanhol (Bem), Catalão (Pouco). |
Prémios e títulos (Awards Prizes, and Honours)
2006 |
Best selected oral presentation at the 4th European Congress of Andrology,
European Academy of Andrology.
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2008 |
First prize for selected oral presentation at the International al Symposium on Assisted Reproduction,
Tambre Foundation.
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2008 |
Lalor Foundation International Travel Award,
American Society of Andrology (ASA) and the ASA International Liasion Committee .
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2008 |
Travel grant to participate in the American Society of Andrology 33rd Annual Meeting,
FLAD.
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2009 |
Scholarship to participate in the MBL Frontiers in Reproduction course,
Burroughs Welcome Fund.
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2009 |
Travel grant to participate in the Frontiers in Reproduction 12th Annual Symposium,
FLAD.
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2010 |
Travel grant to participate in the 6th European Congress of Andrology,
European Academy of Andrology and International Netweork for Young Researchers in Male Fertility.
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2011 |
Young Researcher Prize at the 33rd Annual Meeting of the British Andrology Society,
British Andrology Society.
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2003 |
PhD grant (SFRH/BD/12665/2003),
Portuguese Foundation for Science and Technology (FCT).
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2009 |
Post Doctoral grant (SFRH/BPD/63120/2009),
Portuguese Foundation for Science and Technology (FCT).
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Membro de Associações Profissionais/Científicas (Professional/Scientific Association membership)
Set/2012 - Actual |
American Society of Andrology, Outros (especifique).
Member of the Trainee Affairs Commitee.
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Out/2010 - Actual |
International Network for Young Researchers in Male Fertility, Outros (especifique).
Board Member (Organization).
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Produção científica, técnica e artística/cultural
(Scientific, technical and artistical/cultural
production)
Capítulos de livros publicados Published book chapters |
1. |
Amaral, Sandra; Amaral, Alexandra; Ramalho-Santos, João. 2013. Aging and male reproductive function: a mitochondrial prespective. In Frontiers in Bioscience, 181 - 197. . On line: Frontiers in Bioscience (scholar edition). Abstract: Researching the effects of aging in the male reproductive system is not trivial. Not only are multiple changes at
molecular, cellular and endocrine levels involved, but any findings must be discussed with variable individual characteristics,
as well as with lifestyle and environmental factors. Age-related changes in the reproductive system include any aspect of
reproductive function, from deregulation of the hypothalamic-pituitary-gonadal axis and of local auto/paracrine interactions,
to effects on testicular stem cells, defects in testicular architecture and spermatogenesis, or sperm with decreased functionality.
Several theories place mitochondria at the hub of cellular events related to aging, namely regarding the accumulation of oxidative
damage to cells and tissues, a process in which these organelles play a prominent role, although alternative theories have
also emerged. However, oxidative stress is not the only process involved in mitochondrial-related aging; mitochondrial energy
metabolism, changes in mitochondrial DNA or in mitochondrial-dependent testosterone production are also important. Crucially,
all these issues are likely interdependent. We will review evidence that suggests that mitochondria constitute a common link
between aging and fertility loss. |
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2. |
Amaral, Alexandra; Sousa, Ana P; Campo, Pedro C; Peregrín, Pedro C; Ramalho-Santos, João. 2011. Bioenergetics and male infertility: from basic science to clinical andrology.. In Bioenergetics, 00 - 00. . Hauppauge NY, USA : Nova Publishing. Abstract: Human sperm is a terminally differentiated cell containing highly condensed DNA, and a paucity of cytoplasm and
intracellular organelles. The single goal of a given spermatozoon is to achieve fertilization. Sperm bioenergetics are crucial
for fertilization potential, given that ATP is required for a myriad of functions, from movement to signaling processes involved
in capacitation and the acrosome reaction. In fact, several bioenergetics-related parameters have been proposed to aid in
the evaluation of sperm functionality and in the diagnosis of male infertility. Interestingly, the nature of the ATP that
fuels distinct sperm–specific processes has been hotly debated for decades. The discussion usually involves the relative importance
of two sugar metabolic pathways: glycolysis (restricted to the fibrous sheath, in the sperm tail) and oxidative phosphorylation
(OXPHOS, occurring in mitochondria, localized in the sperm midpiece). Although a growing body of data seems to suggest that
glycolysis has a preponderant role in human sperm, OXPHOS seems to also be relevant, and other metabolic pathways are most
likely involved. In addition, oxidation reactions occurring in sperm mitochondria can be accompanied by the production of
reactive oxygen species (ROS), which, although important for normal signaling pathways, may also cause sperm dysfunction.
The importance of human sperm mitochondria will be discussed, together with the clinical relevance of monitoring a number
of mitochondrial features, from the genome and proteome levels (sperm mitochondrial DNA and proteins) to cellular features
(mitochondrial membrane potential). |
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3. |
Ramalho-Santos, João; Amaral, Alexandra; Sousa, Ana P; Rodrigues, Ana S; Martins, Luís; Baptista, Marta; Mota, Paula C; Tavares, Renata; Amaral, Sandra; Gamboa, Sandra. 2007. Probing the structure and function of mammalian sperm using optical and fluorescence microscopy. In Modern Research and Educational Topics in Microscopy, 394 - 402. ISBN: 978-84-611-9419-3. Spain: FORMATEX. Abstract: Different aspects of sperm function can be monitored with a wide array of microscopy techniques, from
simple optical microscopy to sophisticated fluorescence microscopy (epifluorescence and confocal), and
the level of analysis may be adjusted and complemented according to specific needs. Cursory assessments
involving sperm number and motility can be easily performed, while more detailed analyses regarding the
status of sperm DNA and mitochondria, or the presence of possible apoptotic markers requires more
elaborate protocols. Herein, we detail several methods routinely used to probe sperm structure and
function, using a variety of microscopy techniques.
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Artigos em revistas com arbitragem científica Papers in periodics with scientific refereeing |
1. |
Amaral, Alexandra; Ramalho-Santos, Joao. 2013. "The male gamete is not a somatic cell - the possible meaning of varying sperm RNA levels", Antioxidants & Redox Signaling 18, 2: 179 - 180.
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2. |
John, Justin C. S; Amaral, Alexandra; Bowles, Emma J; Oliveira, João F; Lloyd, Rhyannon; Freitas, Mariana; Grey, Heather L; Navara, Christopher S; Oliveira, Gisela; Schatten, Gerald P; Ramalho-Santos, João. 2006. "The analysis of mitochondria and mitochondrial DNA in human embryonic stem cells", Methods in Molecular Biology, 331: 347 - 374. Abstract: As human embryonic stem cells (hESCs) undergo differentiation, they express genes characteristic of the lineage
for which they are destined. However, fully differentiated individual cell types can be characterized by the number of mitochondria
they possess and the copies of the mitochondrial genome per mitochondrion. These characteristics are indicative of a specific
cell's requirement for adenosine triphosphate (ATP) and therefore cellular viability and function. Consequently, failure for
an ESC to possess the full complement of mitochondria and mitochondrial DNA (mtDNA) could limit its final commitment to a
particular fate. We describe a series of protocols that analyze the process of cellular mitochondrial and mtDNA differentiation
during hESC differentiation. In addition, mtDNA transcription and replication are key events in cellular differentiation that
require interaction between the nucleus and the mitochondrion. To this extent, we describe a series of protocols that analyze
the initiation of these key events as hESCs progress from their undifferentiated state to the fully committed cell. Last,
we describe real-time polymerase chain reaction protocols that allow both the identification of mtDNA copy number and determine
whether mtDNA copy is uniform (homoplasmy) in its transmission or heterogeneous (heteroplasmy).
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Artigos em revistas sem arbitragem científica Papers in periodics without scientific refereeing |
1. |
Amaral, A.; Castillo, J.; Estanyol, J. M; Ballesca, J. L; Ramalho-Santos, J.; Oliva, R.. 2013. "Human Sperm Tail Proteome Suggests New Endogenous Metabolic Pathways", Molecular & Cellular Proteomics 12, 2: 330 - 342. Abstract: Proteomic studies are contributing greatly to our understanding of the sperm cell, and more detailed descriptions
are expected to clarify additional cellular and molecular sperm attributes. The aim of this study was to characterize the
subcellular proteome of the human sperm tail and, hopefully, identify less concentrated proteins (not found in whole cell
proteome studies). Specifically, we were interested in characterizing the sperm metabolic proteome and gaining new insights
into the sperm metabolism issue. Sperm were isolated from normozoospermic semen samples and depleted of any contaminating
leukocytes. Tail fractions were obtained by means of sonication followed by sucrose-gradient ultracentrifugation, and their
purity was confirmed via various techniques. Liquid chromatography and tandem mass spectrometry of isolated sperm tail peptides
resulted in the identification of 1049 proteins, more than half of which had not been previously described in human sperm.
The categorization of proteins according to their function revealed two main groups: proteins related to metabolism and energy
production (26%), and proteins related to sperm tail structure and motility (11%). Interestingly, a great proportion of the
metabolic proteome (24%) comprised enzymes involved in lipid metabolism, including enzymes for mitochondrial beta-oxidation.
Unexpectedly, we also identified various peroxisomal proteins, some of which are known to be involved in the oxidation of
very long chain fatty acids. Analysis of our data using Reactome suggests that both mitochondrial and peroxisomal pathways
might indeed be active in sperm, and that the use of fatty acids as fuel might be more preponderant than previously thought.
In addition, incubation of sperm with the fatty acid oxidation inhibitor etomoxir resulted in a significant decrease in sperm
motility. Contradicting a common concept in the literature, we suggest that the male gamete might have the capacity to obtain
energy from e.
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2. |
Tüttelmann, F.; De Gendt, K; Amaral, A.; Giachini C, C; Welsh, M.; Blomberg Jensen, M; Nurmio, M.; Wahlgren, A.; Stukenborg, J. B. 2012. "The future of testis research is turning 6! Six years of International Network for Young Researchers in Male Fertility", International Journal of Andrology 35, 2: 211 - 213. Abstract: The 'International Network for Young Researchers in Male Fertility' has now turned 6 years old and offers a platform
that stimulates scientific exchange as well as the development of international cooperation for young researchers. We report
on our scope and the exciting achievements, amongst others, the continually increasing number of participants and the growing
success of our annual meetings.
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3. |
Amaral, Alexandra; Wahlgren, Aida; Tüttelmann, Frank; De Gendt, K; Blomberg Jensen, M; Nurmio, Mirja; Welsh, Michelle; Stukenborg, Jan-Bernd. 2012. "Minutes of the 5th Meeting of the International Network for Young Researchers in Male Fertility", Asian Journal of Andrology 14, 5: 796 - 796.
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Sousa, Ana P; Amaral, Alexandra; Baptista, Marta; Tavares, Renata; Caballero Campo, P; Caballero Peregrín, P; Freitas, Albertina; Paiva, Artur; Almeida-Santos, Teresa; Ramalho-Santos, João. 2011. "Not All Sperm Are Equal: Functional Mitochondria Characterize a Subpopulation of Human Sperm with Better Fertilization Potential", PLoS ONE 6, 3: 18112 - 18112. Abstract: Human sperm samples are very heterogeneous and include a low amount of truly functional gametes. Distinct strategies
have been developed to characterize and isolate this specific subpopulation. In this study we have used fluorescence microscopy
and fluorescence-activated cell sorting to determine if mitochondrial function, as assessed using mitochondrial-sensitive
probes, could be employed as a criterion to obtain more functional sperm from a given ejaculate. We first determined that
mitochondrial activity correlated with the quality of distinct human samples, from healthy donors to patients with decreased
semen quality. Furthermore, using fluorescence-activated cell sorting to separate sperm with active and inactive mitochondria
we found that this was also true within samples. Indeed, sperm with active mitochondria defined a more functional subpopulation,
which contained more capacitated and acrosome intact cells, sperm with lower chromatin damage, and, crucially, sperm more
able to decondense and participate in early development using both chemical induction and injection into mature bovine oocytes.
Furthermore, cell sorting using mitochondrial activity produced a more functional sperm subpopulation than classic swim-up,
both in terms of improvement in a variety of functional sperm parameters and in statistical significance. In conclusion, whatever
the true biological role of sperm mitochondria in fertilization, mitochondrial activity is a clear hallmark of human sperm
functionality.
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5. |
Amaral, Alexandra; Paiva, Carla; Baptista, Marta; Sousa, Ana P; Ramalho-Santos, João. 2011. "Exogenous glucose improves long-standing human sperm motility, viability, and mitochondrial function", Fertility and Sterility 96, 4: 848 - 850. Abstract: A relevant fraction of human sperm can be maintained in simple phosphate-buffered saline (PBS) for more than 1 week
at room temperature, a time that could be doubled if glucose was available. This does not seem to be directly due to sperm
mitochondrial activity.
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Amaral, A.; Ramalho-Santos, J.. 2010. "Assessment of mitochondrial potential: implications for the correct monitoring of human sperm function", International Journal of Andrology 33, 1: 180 - 186. Abstract: Mitochondrial membrane potential (MMP) is an indicator of sperm functionality that can be assessed using specific
fluorescent markers. However, the ability of distinct probes to dynamically evaluate sperm MMP has not been determined. In
the present study, human sperm samples were independently labelled with MitoTracker Green, MitoTracker Red and JC-1. The ability
of each probe to correctly monitor MMP was determined by incubating sperm with MMP disruptors (KCN, FCCP and valinomycin).
Similarly, the effect of distinct fixatives (formaldehyde and methanol) was also tested. The three mitochondrial probes provided
similar results, and were able to monitor changes in MMP when sperm had been previously incubated with MMP-disrupting agents.
However, only JC-1 could, to a small extent, mirror MMP alterations after sperm labelling. Unexpectedly, the three probes
were able to stain some pre-fixed sperm, even though this behaviour was very variable, especially for MitoTrackers. On the
other hand, none of the probes was shown to be reliably fixable. Of the three probes tested JC-1 seems to be the most adequate,
nevertheless, the choice of an MMP-specific probe may depend on the aim of each experimental setting and appropriate controls
must always be performed.
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Ramalho-Santos, J.; Varum, S.; Amaral, S.; Mota, P. C; Sousa, A. P; Amaral, A.. 2009. "Mitochondrial functionality in reproduction: from gonads and gametes to embryos and embryonic stem cells", Human Reproduction Update 15, 5: 553 - 572. Abstract
BACKGROUND: Mitochondria are multitasking organelles involved in ATP synthesis, reactive oxygen species (ROS) production,
calcium signalling and apoptosis; and mitochondrial defects are known to cause physiological dysfunction, including infertility.
The goal of this review was to identify and discuss common themes in mitochondrial function related to mammalian reproduction.
METHODS: The scientific literature was searched for studies reporting on the several aspects of mitochondrial activity in
mammalian testis, sperm, oocytes, early embryos and embryonic stem cells.
RESULTS: ATP synthesis and ROS production are the most discussed aspects of mitochondrial function. Metabolic shifts from
mitochondria-produced ATP to glycolysis occur at several stages, notably during gametogenesis and early embryo development,
either reflecting developmental switches or substrate availability. The exact role of sperm mitochondria is especially controversial.
Mitochondria-generated ROS function in signalling but are mostly described when produced under pathological conditions. Mitochondria-based
calcium signalling is primarily important in embryo activation and embryonic stem cell differentiation. Besides pathologically
triggered apoptosis, mitochondria participate in apoptotic events related to the regulation of spermatogonial cell number,
as well as gamete, embryo and embryonic stem cell quality. Interestingly, data from knock-out (KO) mice is not always straightforward
in terms of expected phenotypes. Finally, recent data suggests that mitochondrial activity can modulate embryonic stem cell
pluripotency as well as differentiation into distinct cellular fates.
CONCLUSIONS:Mitochondria-based events regulate different aspects of reproductive function, but these are not uniform throughout
the several systems reviewed. Low mitochondrial activity seems a feature of 'stemness', being described in spermatogonia,
early embryo, inner cell mass cells and embryonic stem cells.
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8. |
Amaral, A.; Ramalho-Santos, J.; St John, J. C. 2007. "The expression of polymerase gamma and mitochondrial transcription factor A and the regulation of mitochondrial DNA content
in mature human sperm", Human Reproduction 22, 6: 1585 - 1596. Abstract
BACKGROUND: Human mitochondrial DNA (mtDNA) encodes 13 polypeptides of the electron transfer chain. Its replication is dependent
on the nuclear-encoded polymerase gamma (POLG) and mitochondrial transcription factor A (TFAM). For POLG, only the polyglutamine
tract, characterized by a series of CAG repeats, has been investigated in human sperm. However, TFAM is associated with the
reduction in mtDNA content of testicular sperm. We have determined whether POLG and TFAM have functional roles in post-ejaculatory
sperm mtDNA.
METHODS: Sperm samples were categorized as: normals, samples with one or two abnormal sperm parameters and oligoasthenoteratozoospermics
(OATs). These were analysed by fluorescent PCR to determine the number of CAG repeats, real-time PCR for mtDNA copy number
and immunocytochemistry and western blotting for patterns of expression for POLG, TFAM and the mtDNA-encoded COXI.
RESULTS: Only the OAT group presented with a significantly higher incidence of heterozygosity for CAG repeats, higher mtDNA
content and a lower percentage of sperm expressing POLG and TFAM. Paradoxically, good-quality sperm had fewer mtDNA copies
but significantly more sperm expressed POLG, TFAM and COXI.
CONCLUSIONS: Our data support the original findings that an association between sperm quality and POLG CAG repeats does exist.
However, the biological significance of these variants in male infertility remains unclear, as these do not seem to affect
mtDNA maintenance. The reduction in mtDNA content in normal samples likely reflects normal spermiogenesis, whereas increases
in POLG and TFAM expression possibly compensate for the low mtDNA content, maintaining mitochondrial homeostasis.
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John, Justin C. S; Bowles, Emma J; Amaral, Alexandra. 2006. "Sperm mitochondria and fertilisation", Society of Reproduction and Fertility Supplement, 65: 399 - 416. Abstract: Human mitochondrial DNA (mtDNA) is an extranuclear genome that encodes 13 of the polypeptides associated with the
process of oxidative phosphorylation (OXPHOS). The role and importance of OXPHOS in sperm motility and function has been debated
over the last few years. Here, we argue that sperm OXPHOS is important to sperm function in the light of clinical based evidence
in the human where pathogenic mutations have also been described in sperm and are associated with varying degrees of male
subfertility. We also discuss the importance of maintaining maternal inheritance of mtDNA and how sperm mtDNA might be eliminated
during early embryogenesis in a manner similar to the process which decreases oocyte mtDNA to extremely low levels once it
reaches the blastocyst stage of preimplantation development. Finally, we discuss the role of sperm mtDNA replication and why
it may be prudent to considerably reduce sperm mtDNA numbers during the transition from spermatogenesis to spermiogenesis.
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10. |
Ramalho-Santos, João; Amaral, Alexandra; Brito, Raquel; Freitas, Mariana; Almeida Santos, T. 2004. "Simultaneous analysis of cytoskeletal patterns and chromosome positioning in human fertilization failures", Fertility and Sterility 82, 6: 1654 - 1659. Abstract
OBJECTIVE: To sequentially and reliably apply both tubulin immunocytochemistry (ICC) and fluorescence in situ hybridization
(FISH) to human fertilization failures, thus providing a tool for a multiple analysis of arrest.
DESIGN: Analysis of human fertilization failures at several stages of arrest.
SETTING: Academic and clinical institutions.
PATIENT(S): Consenting patients undergoing assisted reproduction technologies.
INTERVENTION(S): Failed fertilizations displaying signs of activation without pronuclear development, or with the absence
of polar body emission or cleavage 48 hours after insemination or microinjection were analyzed. Fertilization failures were
fixed and processed for ICC. After data was collected the same samples were then subjected to FISH analysis using probes for
chromosomes X, Y, and 18.
MAIN OUTCOME MEASURE(S): Simultaneous ICC and FISH data on the same sample.
RESULT(S): Sequential application of straightforward standard ICC and FISH techniques was not possible, as the morphologic
features had been altered, microtubular patterns were not preserved, and many samples were rendered opaque. Only chromatin
at the cell surface or outside the oocyte/zygote, such as metaphase II spindles or polar body nuclei, could be routinely probed
for FISH after ICC. However, an increase in detergent-induced sample permeabilization as well as the removal of several steps
usually performed for FISH made it possible to directly compare microtubular patterns and chromosome position, regardless
of chromatin status.
CONCLUSION(S): Analysis of specific proteins by immunocytochemistry and of chromosome status/positioning by FISH can be carried
out sequentially in human fertilization failures, irrespective of the stage of arrest.
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Trabalhos completos/resumidos em eventos sem arbitragem científica Papers in conference proceedings without scientific refereeing |
1. |
Amaral, Alexandra; Castillo, Judit; Mateo, Sara; Ballescà, José L; Ramalho-Santos, João; Oliva, Rafael. 2011. "Human sperm tail proteomics", Trabalho apresentado em XII Jornada de Biologia de la Reproducció, In Biologia de la Reproducció, Barcelona. |
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2. |
Amaral, Alexandra; Sousa, Ana P; Ramalho-Santos, João. 2010. "Subpopulations of human sperm with functional mitochondria have higher fertilization potential.", Trabalho apresentado em 6th European Congress of Andrology, In International Journal of Andrology, Athens, Greece. |
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3. |
Amaral, Alexandra; Campo, Pedro C; Sousa, Ana P; Ramalho-Santos, João; Peregrín, Pedro C. 2009. "Sperm functional parameters characterise better quality subpopulations of human sperm: a preliminary study", Trabalho apresentado em 9th International Congress of Andrology, In Journal of Andrology, Barcelona, Spain. |
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4. |
Campo, Pedro C; Amaral, Alexandra; Sousa, Ana P; Ramalho-Santos, João; Peregrín, Pedro C. 2009. "La correlación multiparamétrica de ensayos funcionales caracteriza las subpoblaciones espermáticas de mayor capacidad fecundante", Trabalho apresentado em 14th National Congress of the Spanish Association of Andrology, 11th Iberian Meeting of Andrology, 4th Iberoamerican Meeting
of Andrology, In Revista Internacional de Andrología, Salud sexual y reproductiva, Barcelona, Spain. |
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5. |
Amaral, Alexandra; Sousa, Ana P; Almeida-Santos, Teresa; Ramalho-Santos, João. 2008. "Human sperm possess subpopulations with different mitochondrial-traits", Trabalho apresentado em American Society of Andrology 33rd Annual Meeting, In Journal of Andrology Supplement, Albuquerque, NM, USA. |
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6. |
Amaral, Alexandra; Sousa, Ana P; Baptista, Marta; Borralho, Ana C; Ramalho-Santos, João. 2008. "Long-term culture: a new approach in the study of human sperm metabolism", Trabalho apresentado em 5th European Congress of Andrology, In International Journal of Andrology, Rome, Italy. |
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7. |
Sousa, Ana P; Amaral, Alexandra; Tavares, Renata; Silva, Rita; Ramalho-Santos, João. 2008. "Functional human sperm subpopulations defined by mitochondrial activity", Trabalho apresentado em 5th European , In International Journal of Andrology, Rome, Italy. |
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8. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. 2006. "Regulation of mitochondrial DNA content in human sperm: implications for male (in)fertility", Trabalho apresentado em 4th European Congress of Andrology, In Andrologie, Toulouse, France. |
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Apresentação oral de trabalho Oral work presentation |
1. |
Amaral, Alexandra; Castillo, Judit; Estanyol, Josep M; Ballescà, José L; Ramalho-Santos, Joao; Oliva, Rafael. Human sperm tail proteomics propose novel metabolic pathways ,17th European Workshop on Molecular and Cellular Endocrinology of the Testis,2012 (Comunicação). |
2. |
Amaral, Alexandra; Castillo, Judit; Estanyol, Josep M; Ballescà, JL; Ramalho-Santos, João; Oliva, Rafael. Human sperm tail proteome suggests novel metabolic clues,33rd Annual Meeting of the British Andrology Society,Birmingham,2011 (Comunicação). |
3. |
Paiva, Carla; Amaral, Alexandra; Baptista, Marta; Sousa, Ana P; Ramalho-Santos, João. Exogenous Glucose improves long-standing human sperm function,4th International Network of Young Researchers in Male Fertility Meeting,Edinburgh,2011 (Poster). |
4. |
Amaral, Alexandra; Castillo, Judit; Mateo, Sara; Ballescà, JL; Ramalho-Santos, João; Oliva, Rafael. Human sperm tail proteomics,XXII Biology of Reproduction Catalan Meeting,Barcelona,2011 (Comunicação). |
5. |
Amaral, Alexandra; Castillo, Judit; Estanyol, Josep M; Ballescà, JL; Ramalho-Santos, João; Oliva, Rafael. Human sperm tail proteome suggests novel metabolic clues,33rd Annual Meeting of the British Andrology Society,Birmingham,2011 (Poster). |
6. |
Amaral, Alexandra; Castillo, Judit; Estanyol, Josep M; Ballescà, JL; Ramalho-Santos, João; Oliva, Rafael. Human sperm tail proteomics,Workshop on Maldi MS-Imaging for Tissues and Biomedical Proteomics,Bacelona,2011 (Comunicação). |
7. |
Amaral, Alexandra. HUMAN SPERM TAIL proteome suggests new metabolic pathways ,University of Barcelona Seminar,Barcelona,2011 (Seminário). |
8. |
Paiva, Carla; Amaral, Alexandra; Baptista, Marta; Sousa, Ana P; Ramalho-Santos, João. Long-term culture: a new approach to the sperm metabolic debate,17th National Congress of Biochemistry,Porto,2010 (Poster). |
9. |
Amaral, Alexandra. Human sperm mitochondrial function: implications to male (in)fertility,III Biochemical Meeting of the University of Trás-os-Montes,Vila Real,2010 (Conferência ou palestra). |
10. |
Amaral, Alexandra; Sousa, Ana P; Ramalho-Santos, João. Subpopulations of human sperm with functional mitochondria have higher fertilization potential,6th European Congress of Andrology,Athens,2010 (Comunicação). |
11. |
Campo, Pedro C; Amaral, Alexandra; Sousa, Ana P; Ramalho-Santos, João; Peregrín, Pedro C. La correlación multiparamétrica de ensayos funcionales caracteriza las subpoblaciones espermáticas de mayor capacidad fecundante,14th National Congress of the Spanish Association of Andrology, 11th Iberian Meeting of Andrology, 4th Iberoamerican Meeting
of Andrology,Barcelona,2009 (Congresso). |
12. |
Amaral, Alexandra; Sousa, Ana P; Baptista, Marta; Ramalho-Santos, João. Long-term culture: a new approach in the study of human sperm metabolism,Frontiers in Reproduction 12th Annual Symposium,Woods Hole, MA,2009 (Simpósio). |
13. |
Amaral, Alexandra; Campo, Pedro C; Sousa, Ana P; Ramalho-Santos, João; Peregrín, Pedro C. Sperm functional parameters characterise better quality subpopulations of human sperm: a preliminary study,9th International Congress of Andrology,Barcelona,2009 (Poster). |
14. |
Sousa, Ana P; Amaral, Alexandra; Tavares, Renata; Silva, Rita; Ramalho-Santos, João. Characterization of subpopulations of human sperm with different competence,Frontiers in Reproduction 12th Annual Symposium,Woods Hole, MA,2009 (Simpósio). |
15. |
Sousa, Ana P; Amaral, Alexandra; Almeida-Santos, Teresa. Current perspectives on the evaluation of sperm functionality,II Portuguese Meeting of Andrology,Coimbra,2009 (Conferência ou palestra). |
16. |
Amaral, Alexandra; Sousa, Ana P; Ramalho-Santos, João. Polarised mitochondria typify functional subpopulations of human sperm,International Symposium on Assisted Reproduction,Madrid,2008 (Simpósio). |
17. |
Sousa, Ana P; Amaral, Alexandra; Tavares, Renata; Baptista, Marta; Silva, Rita; Ramalho-Santos, João. Evaluation of chromatin status and of distinct functional subpopulations in human sperm,6th Centre for Neuroscience and Cell Biology Meeting,Cantanhede,2008 (Comunicação). |
18. |
Amaral, Alexandra; Sousa, Ana P; Almeida-Santos, Teresa; Ramalho-Santos, João. Human sperm possess subpopulations with different mitochondrial-traits,American Society of Andrology 33rd Annual Meeting,Albuquerque, NM,2008 (Poster). |
19. |
Sousa, Ana P; Amaral, Alexandra; Tavares, Renata; Baptista, Marta; Ramalho-Santos, João. Mitochondrial activity defines distinctly functional subpopulations in human sperm,Society for Reproduction and Fertility Conference,Edinburgh,2008 (Poster). |
20. |
Amaral, Alexandra; Sousa, Ana P; Baptista, Marta; Borralho, Ana C; Ramalho-Santos, João. Long-term culture: a new approach in the study of human sperm metabolism,5th European Congress of Andrology,Rome,2008 (Poster). |
21. |
Sousa, Ana P; Amaral, Alexandra; Tavares, Renata; Silva, Rita; Ramalho-Santos, João. Functional human sperm subpopulations defined by mitochondrial activity,5th European Congress of Andrology,Rome,2008 (Poster). |
22. |
Amaral, Alexandra; Sousa, Ana P; Almeida-Santos, Teresa; Ramalho-Santos, João. Subpopulations of human sperm present distinct mitochondrial-related features,Gordon Research Conference on Fertilization & Activation of Development,Plymouth, NH,2007 (Poster). |
23. |
Amaral, Alexandra; Sousa, Ana P; Almeida-Santos, Teresa; Ramalho-Santos, João. Human sperm possess subpopulations with different mitochondrial-attributes,National Meeting MICRO’07 BIOTEC – XXXIII JPG,Lisbon,2007 (Poster). |
24. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. Regulation of mitochondrial DNA content in human sperm: implications for male (in)fertility,4th European Congress of Andrology,Toulouse,2006 (Congresso). |
25. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. Regulation of mitochondrial DNA content in human sperm: implications for male (in)fertility,4th Centre for Neuroscience and Cell Biology Meeting,Cantanhede,2006 (Comunicação). |
26. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. Mitochondrial DNA replication factors in human spermatozoa,10th International Symposium on Spermatology,San Lorenzo de El Escorial, Madrid,2006 (Poster). |
27. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. Regulation of mitochondrial DNA content in human sperm: implications for male (in)fertility,15th National Meeting of Biochemistry,Aveiro,2006 (Poster). |
28. |
Amaral, Alexandra; Ramalho-Santos, João; John, Justin C. S. Mitochondrial DNA variance and male infertility,2nd Centre for Neuroscience and Cell Biology meeting,Luso,2004 (Comunicação). |
29. |
Amaral, Alexandra; Brito, Raquel; Freitas, Mariana; Almeida-Santos, Teresa; Ramalho-Santos, João. Simultaneous analysis of human fertilization failures by immunocytochemistry and FISH,3rd Portuguese-Spanish Biophysics Meeting,Lisbon,2004 (Poster). |
Organização de evento Event organization |
1. |
Amaral, Alexandra; Castillo, Judit; Wahlgren, Aida; Tüttelmann, Frank; Gendt, Karel D; Stukenborg, Jan-Bernd; Nurmio, Mirja; Chianese, Chiara; Kläver, Ruth; Björkgren, Ida; Jørgensen, Anne; Welsh, Michelle. 6th Meeting of the International Network for Young Researchers in Male Fertility,2013 (Congresso). |
2. |
Amaral, Alexandra; Wahlgren, Aida; Blomberg Jensen, M; Stukenborg, Jan-Bernd; De Gendt, K; Welsh, Michelle; Nurmio, Mirja; Tüttelmann, Frank. 5th Meeting of the Interanational Network of Young Researchers in Male Fetility,2012 (Congresso). |
3. |
Amaral, Alexandra; Tüttelmann, Frank; Jensen, Martin B; Gendt, Karel D; Giachini, Claudia; Nurmio, Mirja; Stukenborg, Jan-Bernd; Wahlgren, Aida; Welsh, Michelle. 4th Meeting of the International Network for Young Researchers in Male Fertility,2011 (Congresso). |
4. |
Ambrósio, Francisco; Ramalho-Santos, João; Rego, Cristina; Castelo-Branco, Gonçalo; Araújo, Inês; Malva, João; Relvas, João; Cabral, Joaquim S; Belo, José; Almeida, Luís; Sousa, Mónica; Sousa, Nuno; Reis, Rui; Outeiro, Tiago; Amaral, Alexandra; Oliveira, Ana C; Silva, Ana C; Sousa, Ana P; Álvaro, Ana R; Carreira, Bruno; Cavadas, Cláudia. 2nd International Meeting of the Portuguese Society for Stem Cells and Cellular Theray,2007 (Encontro / Organização). |
Outra produção técnica Other technical production |
1. |
Amaral, Alexandra. Human sperm mitochondrial function: implications for male (in)fertility,2008. |
Dados Complementares (Additional data)
Dissertação de Mestrado Master degree dissertation |
1. |
Carla Patrícia Rodrigues Paiva, Vias metabólicas e funcionalidade de espermatozóides humanos, 2009. Dissertação (Mestrado em Biologia Celular) - Universidade de Coimbra (Co-orientador). |
Orientação de outra natureza Other orientation |
1. |
Carla Patrícia Rodrigues Paiva, Avaliação de diversos parâmetros funcionais em culturas em suspensão de espermatozóides, 2009. Centro de Neurociências e Biologia Celular (Orientador). |
Participação no júri de Graus Académicos Academic Degrees jury participation |
1. |
Alexandra Amaral; João Ramalho-Santos; Armando Cristóvão; Sandra Amaral. Participação no júri de Andreia Filipa Neves Silva. Human sperm chromatin integrity evaluation: clinical relevance., 2012. Dissertação (Mestrado em Biologia Celular) - Universidade de Coimbra. |
2. |
Alexandra Amaral; João Ramalho-Santos; Armando Cristóvão; Paulo Santos. Participação no júri de Leonor Cruz Fernandes. Calcium Mobilisation in Human Sperm and its Effects on Motility., 2012. Dissertação (Mestrado em Biologia Celular) - Universidade de Coimbra. |
3. |
Alexandra Amaral; João Ramalho-Santos; Rui de Carvalho; Carlos Palmeira. Participação no júri de Carla Patrícia Rodrigues Paiva. Metabolic pathways and human sperm function, 2010. Dissertação (Mestrado em Biologia Celular) - Universidade de Coimbra. |
Participação em eventos Event participation |
Participação como Membro da Comissão Científica Participation as Member of the Program Committee |
1. |
6th Meeting of the International Network for Young Researchers in Male Fertility, 2013 (Congresso). |
2. |
5th Meeting of the International Network for Young Researchers in Male Fertility, 2012 (Congresso). |
3. |
4th Meeting of the International Network for Young Researchers in Male Fertility, 2011 (Congresso). |
Indicadores de produção
(Production indicators)
Produção científica
Scientific production |
Produção técnica
Technical production |
Dados complementares
data |
Produção científica Scientific production |
23 |
Livros e capítulos Books and book chapters |
3 |
Capítulos de livros publicados Published book chapters |
3 |
Artigos científicos em revistas Papers in periodics |
12 |
Com arbitragem científica With scientific refereeing |
2 |
Sem arbitragem científica Without scientific refereeing |
10 |
Trabalhos em eventos Papers in conference proceedings |
8 |
Sem arbitragem científica Without scientific refereeing |
8 |
Produção técnica Technical production |
34 |
Outros tipos de produção técnica Other technical production |
34 |
Dados complementares (Additional data) |
8 |
Orientações Orientations |
2 |
Participação no Júri de Graus Académicos Academic Degrees jury participation |
3 |
Participação em Eventos Event participation |
3 |
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