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1.
Plant Cell ; 31(12): 3092-3112, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31575724

RESUMO

Xanthophylls are a class of carotenoids that are important micronutrients for humans. They are often found esterified with fatty acids in fruits, vegetables, and certain grains, including bread wheat (Triticum aestivum). Esterification promotes the sequestration and accumulation of carotenoids, thereby enhancing stability, particularly in tissues such as in harvested wheat grain. Here, we report on a plant xanthophyll acyltransferase (XAT) that is both necessary and sufficient for xanthophyll esterification in bread wheat grain. XAT contains a canonical Gly-Asp-Ser-Leu (GDSL) motif and is encoded by a member of the GDSL esterase/lipase gene family. Genetic evidence from allelic variants of wheat and transgenic rice (Oryza sativa) calli demonstrated that XAT catalyzes the formation of xanthophyll esters. XAT has broad substrate specificity and can esterify lutein, ß-cryptoxanthin, and zeaxanthin using multiple acyl donors, yet it has a preference for triacylglycerides, indicating that the enzyme acts via transesterification. A conserved amino acid, Ser-37, is required for activity. Despite xanthophylls being synthesized in plastids, XAT accumulated in the apoplast. Based on analysis of substrate preferences and xanthophyll ester formation in vitro and in vivo using xanthophyll-accumulating rice callus, we propose that disintegration of the cellular structure during wheat grain desiccation facilitates access to lutein-promoting transesterification.plantcell;31/12/3092/FX1F1fx1.


Assuntos
Hidrolases de Éster Carboxílico/metabolismo , Luteína/metabolismo , Triticum/enzimologia , Xantofilas/metabolismo , Alelos , beta-Criptoxantina/metabolismo , Biocatálise , Hidrolases de Éster Carboxílico/genética , Carotenoides/metabolismo , Esterificação , Ésteres/metabolismo , Especificidade de Órgãos/genética , Oryza/metabolismo , Plantas Geneticamente Modificadas , Plastídeos/metabolismo , Triglicerídeos/metabolismo , Triticum/embriologia , Triticum/genética , Triticum/metabolismo , Zeaxantinas/metabolismo
2.
J Paediatr Child Health ; 58(4): 630-635, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34773316

RESUMO

Several studies have demonstrated a high incidence of autistic spectrum features in individuals with Smith-Lemli-Opitz syndrome (SLOS). However, do these findings imply a converse relationship that has diagnostic utility? Is SLOS testing implicated when autism spectrum disorder (ASD) is the only clinical indication? AIM: To determine if there is any correlation with a clinical indication of ASD and a biochemical diagnosis of SLOS, based on historical test request and assay data. METHODS: Six years (2008-2013) of clinical test requests for 7-dehydrocholesterol (7-DHC) level were classified and summarised according to indication and final test result. RESULTS: From the audit period, 988 valid test results from post-natal samples were identified. In plasma/serum, mean 7-DHC level was 264.7 µmol/L (normal range < 2.0) for confirmed SLOS cases. No tests performed due to an isolated clinical indication of ASD or where no clinical information was supplied were associated with 7-DHC levels diagnostic for SLOS. CONCLUSIONS: Historical test data analysis supports the recommendation that autism/ASD as a single clinical feature is not an appropriate indication for SLOS (7-DHC) biochemical testing.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Síndrome de Smith-Lemli-Opitz , Transtorno do Espectro Autista/diagnóstico , Transtorno Autístico/diagnóstico , Humanos , Valores de Referência , Síndrome de Smith-Lemli-Opitz/diagnóstico
3.
Genome ; 64(1): 29-38, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33002386

RESUMO

Cereal rye and its wild forms are important sources of genetic diversity for wheat breeding due to their resistances to biotic and abiotic stresses. Secale strictum subsp. anatolicum (Boiss.) K. Hammer (SSA) is a weedy relative of cultivated rye, S. cereale. Meiotic chromosome pairing in F1 hybrids of SSA and S. cereale reveals strong genomic affinity between the two genomes. A study of the transferability of S. cereale sequence-based markers to SSA and hexaploid triticale demonstrated their applicability for tracing SSA chromatin in wheat. The transferability of the markers was over 80% from homoeologous groups 1, 2, and 3, and greater than 70% from groups 4 to 7. This study focused on the generation and molecular and cytogenetic characterization of wheat-SSA alien derivatives. Twelve were identified using combinations of non-denaturing fluorescence in situ hybridization (ND-FISH), genomic in situ hybridization (GISH), and molecular marker analysis. All SSA chromosomes, except 3Ra and 6Ra, were transferred to wheat either in the form of monosomic additions (MA), mono-telosomic additions (MtA), double-mono-telosomic additions (dMtA), or double-monosomic additions (dMA). The germplasm developed in this study will help to enhance the genetic base of wheat and facilitate molecular breeding of wheat and triticale.


Assuntos
Melhoramento Vegetal , Secale/genética , Triticale/genética , Triticum/genética , Cromossomos de Plantas , Análise Citogenética , Resistência à Doença/genética , Genômica , Hibridização Genética , Hibridização in Situ Fluorescente , Cariótipo , Doenças das Plantas/genética
4.
Mol Genet Metab ; 131(1-2): 197-205, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32739280

RESUMO

The cause of neurodegeneration in MPS mouse models is the focus of much debate and what the underlying cause of disease pathology in MPS mice is. The timing of development of pathology and when this can be reversed or impacted is the key to developing suitable therapies in MPS. This study is the first of its kind to correlate the biochemical changes with the functional outcome as assessed using non-invasive behaviour testing across multiple mucopolysaccharidosis (MPS) mouse models. In the MPS brain, the primary lysosomal enzyme dysfunction leads to accumulation of primary glycosaminoglycans (GAGs) with gangliosides (GM2 and GM3) being the major secondary storage products. With a focus on the neuropathology, a time course experiment was conducted in MPS I, MPS IIIA, MPS VII (severe and attenuated models) in order to understand the relative timing and level of GAG and ganglioside accumulation and how this correlates to behaviour deficits. Time course analysis from 1 to 6 months of age was conducted on brain samples to assess primary GAG (uronic acid), ß-hexosaminidase enzyme activity and levels of GM2 and GM3 gangliosides. This was compared to a battery of non-invasive behaviour tests including open field, inverted grid, rotarod and water cross maze were assessed to determine effects on motor function, activity and learning ability. The results show that the GAG and ganglioside accumulation begins prior to the onset of detectable changes in learning ability and behaviour. Interestingly, the highest levels of GAG and ganglioside accumulation was observed in the MPS IIIA mouse despite having 3% residual enzyme activity. Deficits in motor function were clearly observed in the severe Gusmps/mps, which were significantly delayed in the attenuated Gustm(L175F)Sly model despite their minimal increase in detectable enzyme activity. This suggests that genotype and residual enzyme activity are not indicative of severity of disease pathology in MPS disease and there exists a window when there are considerable storage products without detectable functional deficits which may allow an alteration to occur with therapy.


Assuntos
Encéfalo/metabolismo , Glucuronidase/genética , Mucopolissacaridose III/metabolismo , Mucopolissacaridose I/metabolismo , Mucopolissacaridose VII/metabolismo , Animais , Encéfalo/patologia , Modelos Animais de Doenças , Gangliosídeo G(M2)/genética , Gangliosídeo G(M2)/metabolismo , Gangliosídeo G(M3)/genética , Gangliosídeo G(M3)/metabolismo , Glicosaminoglicanos/genética , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/metabolismo , Humanos , Masculino , Aprendizagem em Labirinto/fisiologia , Camundongos , Mucopolissacaridose I/genética , Mucopolissacaridose I/patologia , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Mucopolissacaridose VII/genética , Mucopolissacaridose VII/patologia
5.
Theor Appl Genet ; 133(7): 2117-2130, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32198597

RESUMO

KEY MESSAGE: A variety of Thinopyrum bessarabicum introgressions in both hexaploid and tetraploid wheats were generated and characterized by molecular cytogenetic analysis. Six wheat-J genome recombinants were identified with ND-FISH and GISH. Diploid wheatgrass, Thinopyrum bessarabicum (2n = 2x = 14, EbEb or JbJb or JJ), is a well-known alien source of salinity tolerance and disease resistance for wheat improvement. The true genetic potential and effect of such introgressions into wheat can be best studied in chromosomal addition or substitution lines. Here, we report the generation and characterization of various categories of Th. bessarabicum derivatives in both hexaploid and tetraploid cultivated wheats. Sequential non-denaturing fluorescence in situ hybridization (ND-FISH) and genomic in situ hybridization (GISH) are robust techniques to visualize the size of alien introgressions and breakpoints. We identified a complete set of monosomic addition lines into both bread wheat and durum wheat, except for 7J in durum wheat, by sequential ND-FISH and GISH. We also characterized alien derivatives belonging to various classes including mono-telosomic additions, disomic additions, monosomic substitutions, double monosomic substitutions, monosomic substitution-monosomic additions, double monosomic additions, and multiple monosomic additions into both bread and durum wheats. In addition, various wheat-Th. bessarabicum recombinant chromosomes were also detected in six alien derivatives. These wheat-Th. bessarabicum derivatives will provide useful cytogenetic resources for improvement of both hexaploid and tetraploid wheats.


Assuntos
Genoma de Planta , Poaceae/genética , Triticum/genética , Mapeamento Cromossômico , Cromossomos de Plantas , Cruzamentos Genéticos , Citogenética , DNA de Plantas/genética , Resistência à Doença/genética , Genótipo , Hibridização in Situ Fluorescente , Cariotipagem , Mitose , Ploidias
6.
Genome ; 63(11): 525-534, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32762630

RESUMO

Sequence-based markers have added a new dimension in the efficiency of identifying alien introgressions in wheat. Expressed sequence tag-sequence tagged sites (EST-STS) markers have proved useful in tracing alien chromatin. In this study, we report the development of Thinopyrum bessarabicum- and Secale anatolicum-specific EST-STS markers and their application in tracing respective alien chromatin introgressions in wheat. The parental lines, Chinese Spring (CS), ISR991.1 (CS/Th. bessarabicum amphidiploid), and ISR1049.2 (CS/Secale anatolicum amphidiploid), were used as core experimental materials. Using comparative analysis of RNA-Seq data, 10 903 and 10 660 candidate sequences specific to Th. bessarabicum and S. anatolicum, respectively, were assembled and identified. To validate the genome specificity of these candidate sequences, 68 and 64 EST-STS markers were developed from randomly selected candidate sequences of Th. bessarabicum and S. anatolicum, respectively, and tested on sets of alien addition lines. Fifty-five and 53 markers for Th. bessarabicum and S. anatolicum chromatin, respectively, were assigned to chromosomal location(s), covering all seven chromosomes. Approximately 83% of S. anatolicum-specific markers were transferable to S. cereale. The genome-specific candidate sequences identified and the EST-STS markers developed will be valuable resources for exploitation of Th. bessarabicum and Secale species diversity in wheat and triticale breeding.


Assuntos
RNA-Seq , Secale/genética , Triticum/genética , Cromossomos de Plantas , Etiquetas de Sequências Expressas , Hibridização in Situ Fluorescente
7.
Ann Hum Biol ; 46(5): 400-408, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31288575

RESUMO

Background: Individual differences in biological maturation impact player selection and development in youth football.Aim: To evaluate players perceptions of competing in a football tournament where they were matched by maturity rather than chronological age.Subjects: Participants included male junior footballers from three professional academies (n = 115).Methods: The study employed multiple methods of analysis, including one sample mean t-tests, equivalence tests, ANOVAs, and thematic analysis of qualitative data derived from open-ended questions.Results and conclusions: Player's perceived the bio-banding format as providing two main benefits. Early maturing players perceived greater physical and technical challenge, and in turn new opportunities and challenges. Late maturing players perceived less physical and technical challenge, yet greater opportunity to demonstrate technical and tactical abilities. The players reported that they enjoyed and understood the purpose of the bio-banded format, and perceived less risk for injury. Players in all three maturity groups reported more opportunity to engage in leadership behaviours, influence game-play, and express themselves on the ball in the bio-banded format. Bio-banding may facilitate development for both early and late maturing academy players by presenting new learning environments and challenges.


Assuntos
Desempenho Atlético , Percepção , Futebol , Adolescente , Criança , Humanos , Masculino , Fatores Etários , Desempenho Atlético/estatística & dados numéricos , Estatura , Estados Unidos , Futebol/psicologia
9.
Nanotechnology ; 28(7): 075302, 2017 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-28074783

RESUMO

The atomistic structure of the tip apex plays a crucial role in performing reliable atomic-scale surface and adsorbate manipulation using scanning probe techniques. We have developed an automated extraction routine for controlled removal of single hydrogen atoms from the H:Si(100) surface. The set of atomic extraction protocols detect a variety of desorption events during scanning tunneling microscope (STM)-induced modification of the hydrogen-passivated surface. The influence of the tip state on the probability for hydrogen removal was examined by comparing the desorption efficiency for various classifications of STM topographs (rows, dimers, atoms, etc). We find that dimer-row-resolving tip apices extract hydrogen atoms most readily and reliably (and with least spurious desorption), while tip states which provide atomic resolution counter-intuitively have a lower probability for single H atom removal.

10.
Magn Reson Med ; 86(4): 1815-1817, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34096094
11.
Mol Genet Metab ; 118(2): 100-10, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27106513

RESUMO

UNLABELLED: Mucopolysaccharidosis IIIA is a heritable neurodegenerative disorder resulting from the dysfunction of the lysosomal hydrolase sulphamidase. This leads to the primary accumulation of the complex carbohydrate heparan sulphate in a wide range of tissues and the secondary neuronal storage of gangliosides GM2 and GM3 in the brain. GM2 storage is associated with CNS deterioration in the GM2 gangliosidosis group of lysosomal storage disorders and may also contribute to MPS CNS disease. N-butyldeoxynojirimycin, an inhibitor of ceramide glucosyltransferase activity and therefore of ganglioside synthesis, was administered to MPS IIIA mice both prior to maximal GM2 and GM3 accumulation (early treatment) and after the maximum level of ganglioside had accumulated in the brain (late treatment) to determine if behaviour was altered by ganglioside level. Ceramide glucosyltransferase activity was decreased in both treatment groups; however, brain ganglioside levels were only decreased in the late treatment group. Learning in the water cross maze was improved in both groups and the innate fear response was also restored in both groups. A reduction in the expression of inflammatory gene Ccl3 was observed in the early treatment group, while IL1ß expression was reduced in both treatment groups. Thus, it appears that NB-DNJ elicits a transient decrease in brain ganglioside levels, some modulation of inflammatory cytokines and a functional improvement in behaviour that can be elicited both before and after overt neurological changes manifest. SYNOPSIS: NB-DNJ improves learning and restores the innate fear response in MPS IIIA mice by decreasing ceramide glucosyltransferase activity and transiently reducing ganglioside storage and/or modulating inflammatory signals.


Assuntos
1-Desoxinojirimicina/análogos & derivados , Inibidores de Glicosídeo Hidrolases/uso terapêutico , Mucopolissacaridose III/tratamento farmacológico , 1-Desoxinojirimicina/farmacologia , 1-Desoxinojirimicina/uso terapêutico , Análise de Variância , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Quimiocina CCL3/metabolismo , Modelos Animais de Doenças , Medo/efeitos dos fármacos , Gangliosídeos/metabolismo , Glucosiltransferases/antagonistas & inibidores , Glucosiltransferases/metabolismo , Inibidores de Glicosídeo Hidrolases/farmacologia , Interleucina-1beta/metabolismo , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Mucopolissacaridose III/metabolismo , Mucopolissacaridose III/psicologia
12.
MAGMA ; 34(3): 323-325, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34013480
13.
Genet Sel Evol ; 47: 100, 2015 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-26718134

RESUMO

BACKGROUND: A major step towards the success of chickens as a domesticated species was the separation between maternal care and reproduction. Artificial incubation replaced the natural maternal behaviour of incubation and, thus, in certain breeds, it became possible to breed chickens with persistent egg production and no incubation behaviour; a typical example is the White Leghorn strain. Conversely, some strains, such as the Silkie breed, are prized for their maternal behaviour and their willingness to incubate eggs. This is often colloquially known as broodiness. RESULTS: Using an F2 linkage mapping approach and a cross between White Leghorn and Silkie chicken breeds, we have mapped, for the first time, genetic loci that affect maternal behaviour on chromosomes 1, 5, 8, 13, 18 and 19 and linkage group E22C19W28. Paradoxically, heterozygous and White Leghorn homozygous genotypes were associated with an increased incidence of incubation behaviour, which exceeded that of the Silkie homozygotes for most loci. In such cases, it is likely that the loci involved are associated with increased egg production. Increased egg production increases the probability of incubation behaviour occurring because egg laying must precede incubation. For the loci on chromosomes 8 and 1, alleles from the Silkie breed promote incubation behaviour and influence maternal behaviour (these explain 12 and 26% of the phenotypic difference between the two founder breeds, respectively). CONCLUSIONS: The over-dominant locus on chromosome 5 coincides with the strongest selective sweep reported in chickens and together with the loci on chromosomes 1 and 8, they include genes of the thyrotrophic axis. This suggests that thyroid hormones may play a critical role in the loss of incubation behaviour and the improved egg laying behaviour of the White Leghorn breed. Our findings support the view that loss of maternal incubation behaviour in the White Leghorn breed is the result of selection for fertility and egg laying persistency and against maternal incubation behaviour.


Assuntos
Comportamento Animal/fisiologia , Galinhas/genética , Mapeamento Cromossômico , Ovos , Comportamento Materno/fisiologia , Locos de Características Quantitativas , Animais , Galinhas/fisiologia , Cruzamentos Genéticos , Feminino , Técnicas de Genotipagem , Polimorfismo de Nucleotídeo Único
14.
Gen Comp Endocrinol ; 213: 1-8, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25687742

RESUMO

Clutch size is a key avian fitness and life history trait. A physiological model for clutch size determination (CSD), involving an anti-gonadal effect of prolactin (PRL) via suppression of luteinizing hormone (LH), was proposed over 20 years ago, but has received scant experimental attention since. The few studies looking at a PRL-based mechanistic hypothesis for CSD have been equivocal, but recent experiments utilizing a pharmacological agent to manipulate PRL in the zebra finch (Taeniopygia guttata) found no support for a role of this hormone in clutch size determination. Here, we take a complementary approach by manipulating clutch size through egg removal, examining co-variation in PRL and LH between two breeding attempts, as well as through experimentally-extended laying. Clutch size increased for egg removal females, but not controls, but this was not correlated with changes in PRL or LH. There were also no differences in PRL between egg removal females and controls, nor did PRL levels during early, mid- or late-laying of supra-normal clutches predict clutch size. By uncoupling PRL, LH and clutch size in our study, several key predictions of the PRL-based mechanistic model for CSD were not supported. However, a positive correlation between PRL levels late in laying and days relative to the last egg (clutch completion) provides an alternative explanation for the equivocal results surrounding the conventional PRL-based physiological model for CSD. We suggest that females coordinate PRL-mediated incubation onset with clutch completion to minimize hatching asynchrony and sibling hierarchy, a behavior that is amplified in females laying larger clutches.


Assuntos
Cruzamento , Tamanho da Ninhada/fisiologia , Tentilhões/fisiologia , Hormônio Luteinizante/metabolismo , Óvulo/fisiologia , Prolactina/metabolismo , Reprodução/fisiologia , Animais , Feminino , Óvulo/citologia
15.
Nature ; 452(7185): 317-22, 2008 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-18354476

RESUMO

Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) beta-subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor-cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.


Assuntos
Coturnix/fisiologia , Fotoperíodo , Hipófise/metabolismo , Hipófise/efeitos da radiação , Reprodução/fisiologia , Reprodução/efeitos da radiação , Tireotropina/metabolismo , Animais , Galinhas , Coturnix/anatomia & histologia , Coturnix/genética , AMP Cíclico/metabolismo , Escuridão , Indução Enzimática , Feminino , Regulação da Expressão Gênica/efeitos da radiação , Genoma , Genômica , Hipotálamo/metabolismo , Hipotálamo/efeitos da radiação , Iodeto Peroxidase/biossíntese , Iodeto Peroxidase/genética , Iodeto Peroxidase/metabolismo , Luz , Hormônio Luteinizante/metabolismo , Masculino , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Hipófise/anatomia & histologia , Receptores da Tireotropina/metabolismo , Estações do Ano , Transdução de Sinais/efeitos da radiação , Testículo/crescimento & desenvolvimento , Tireotropina/administração & dosagem , Tireotropina/antagonistas & inibidores , Tireotropina/imunologia
16.
Gen Comp Endocrinol ; 202: 26-34, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24768674

RESUMO

Clutch size is a fundamental predictor of avian fitness, widely-studied from evolutionary and ecological perspectives, but surprisingly little is known about the physiological mechanisms regulating clutch size variation. The only formal mechanistic hypothesis for avian clutch-size determination predicts an anti-gonadal effect of circulating prolactin (PRL) via the inhibition of luteinizing hormone (LH), and has become widely-accepted despite little experimental support. Here we investigated the relationship between pre-breeding and breeding plasma PRL and LH and clutch-size in captive-breeding female zebra finches (Taeniopygia guttata). Using a repeated-measures design, we followed individual females from pre-breeding, through multiple breeding attempts, and attempted to decrease PRL using the D2-receptor agonist, bromocriptine. Clutch size was independent of variation in pre-breeding PRL or LH, although pre-breeding LH was negatively correlated with the time between pairing and the onset of laying. Clutch size was independent of variation in plasma PRL on all days of egg-laying. Bromocriptine treatment had no effect on plasma PRL, but in this breeding attempt clutch size was also independent of plasma PRL. Finally, we found no evidence for an inverse relationship between plasma PRL and LH levels, as predicted if PRL had inhibitory effects via LH. Thus, our data fail to provide any support for the involvement of circulating PRL in clutch size determination. These findings suggest that alternative models for hormonal control of avian clutch size need to be considered, perhaps involving downstream regulation of plasma PRL at the level of the ovary, or other hormones that have not been considered to date.


Assuntos
Tamanho da Ninhada/fisiologia , Tentilhões/sangue , Tentilhões/fisiologia , Hormônio Luteinizante/sangue , Prolactina/sangue , Reprodução/fisiologia , Animais , Cruzamento , Bromocriptina/farmacologia , Tamanho da Ninhada/efeitos dos fármacos , Feminino , Masculino , Oviposição/efeitos dos fármacos , Reprodução/efeitos dos fármacos
17.
Gen Comp Endocrinol ; 190: 164-9, 2013 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-23470654

RESUMO

Many bird species have advanced their seasonal timing in response to global warming, but we still know little about the causal effect of temperature. We carried out experiments in climate-controlled aviaries to investigate how temperature affects luteinizing hormone, prolactin, gonadal development, timing of egg laying and onset of moult in male and female great tits. We used both natural and artificial temperature patterns to identify the temperature characteristics that matter for birds. Our results show that temperature has a direct, causal effect on onset of egg-laying, and in particular, that it is the pattern of increase rather than the absolute temperature that birds use. Surprisingly, the pre-breeding increases in plasma LH, prolactin and in gonadal size are not affected by increasing temperature, nor do they correlate with the onset of laying. This suggests that the decision to start breeding and its regulatory mechanisms are fine-tuned by different factors. We also found similarities between siblings in the timing of both the onset of reproduction and associated changes in plasma LH, prolactin and gonadal development. In conclusion, while temperature affects the timing of egg laying, the neuroendocrine system does not seem to be regulated by moderate temperature changes. This lack of responsiveness may restrain the advance in the timing of breeding in response to climate change. But as there is heritable genetic variation on which natural selection can act, microevolution can take place, and may represent the only way to adapt to a warming world.


Assuntos
Oviposição/fisiologia , Passeriformes/metabolismo , Passeriformes/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Mudança Climática , Feminino , Temperatura
18.
Phys Med ; 106: 102515, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36630805

RESUMO

One of the aims of EFOMP is to organise events for education, training and continuous professional development. For this reason, the European Federation of Organisations for Medical Physics has developed a series of schools, called the European School for Medical Physics Experts (ESMPE). These are designed for medical physicists working as Medical Physics Experts (MPE) or in training to become an MPE and the level of training is at EQF level 8. The quality of training offered is accredited by the European Board for Accreditation in Medical Physics.EFOMP schoolstarget new topics included in the revised core curricula and guidelines for Medical Physics Experts in various subspecialties, which are rapidly evolving, as well as areas where the Medical Physicist plays a key role. The 28th ESMPE school was entitled "Statistics in Medical Physics".


Assuntos
Currículo , Física Médica , Física Médica/educação
19.
Am Nat ; 179(2): E55-69, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22218320

RESUMO

Timing of reproduction in temperate-zone birds is strongly correlated with spring temperature, with an earlier onset of breeding in warmer years. Females adjust their timing of egg laying between years to be synchronized with local food sources and thereby optimize reproductive output. However, climate change currently disrupts the link between predictive environmental cues and spring phenology. To investigate direct effects of temperature on the decision to lay and its genetic basis, we used pairs of great tits (Parus major) with known ancestry and exposed them to simulated spring scenarios in climate-controlled aviaries. In each of three years, we exposed birds to different patterns of changing temperature. We varied the timing of a temperature change, the daily temperature amplitude, and the onset and speed of a seasonal temperature rise. We show that females fine-tune their laying in response to a seasonal increase in temperature, whereas mean temperature and daily temperature variation alone do not affect laying dates. Luteinizing hormone concentrations and gonadal growth in early spring were not influenced by temperature or temperature rise, possibly posing a constraint to an advancement of breeding. Similarities between sisters in their laying dates indicate genetic variation in cue sensitivity. These results refine our understanding of how changes in spring climate might affect the mismatch in avian timing and thereby population viability.


Assuntos
Fotoperíodo , Reprodução , Aves Canoras/fisiologia , Temperatura , Animais , Sinais (Psicologia) , Feminino , Laparotomia/veterinária , Hormônio Luteinizante/sangue , Masculino , Muda , Países Baixos , Ovário/crescimento & desenvolvimento , Modelos de Riscos Proporcionais , Estações do Ano , Testículo/crescimento & desenvolvimento
20.
Horm Behav ; 61(5): 741-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22504307

RESUMO

The Challenge Hypothesis postulates that male vertebrates can respond to social challenges, such as simulated territorial intrusions, by rapidly increasing their concentrations of plasma androgens, such as testosterone (T). This increase may facilitate the expression of aggressive behavior and lead to persistence of this behavior even after withdrawal of the challenge, thus potentially promoting territoriality and the probability of winning future challenges. The scope of the Challenge Hypothesis was tested by exposing free-ranging male Cassin's Sparrows, Peucaea cassinii, to conspecific song playback (SPB) at the beginning of the vernal nesting season. Exposure to SPB stimulated aggressive behavior but did not influence plasma T. Furthermore, plasma T did not correlate with the duration of exposure to SPB, and the behavioral response to SPB did not differ in males that were challenged a second time shortly after the first challenge. As birds were investigated at a stage of their reproductive cycle when plasma T is presumably seasonally high due to photostimulation, the lack of hormonal response to SPB may have been due to the hypothalamus-pituitary-gonadal axis secreting hormones at maximum rates. This was not the case, however, because administration of gonadotropin-releasing hormone I rapidly stimulated the secretion of luteinizing hormone (LH) and T, and treatment with ovine LH rapidly stimulated T secretion.


Assuntos
Comportamento Animal/fisiologia , Comportamento de Retorno ao Território Vital , Hormônios/metabolismo , Pardais/fisiologia , Vocalização Animal/fisiologia , Algoritmos , Animais , Animais Selvagens/sangue , Animais Selvagens/metabolismo , Animais Selvagens/fisiologia , Voo Animal/fisiologia , Hormônio Liberador de Gonadotropina/sangue , Hormônio Liberador de Gonadotropina/metabolismo , Comportamento de Retorno ao Território Vital/fisiologia , Hormônios/sangue , Hormônio Luteinizante/sangue , Hormônio Luteinizante/metabolismo , Masculino , Comportamento Sexual Animal/fisiologia , Pardais/sangue , Pardais/metabolismo , Territorialidade , Testosterona/sangue , Testosterona/metabolismo
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