CIISA - Artigos em revistas internacionais
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- Funcionalidades dos RNA não codificantes (ncRNA) e pequenos RNA reguladores, nos mamíferosPublication . Dias Correia, José Henrique Rocha; Dias Correia, António AgostinhoOs ácidos ribonucleicos não codificadores de proteínas (ncRNA) são um importante conjunto de RNA dentro da totalidade dos transcritos existentes nas células animais. Os ncRNA contêm nas suas moléculas informações variadas que lhes permitem ter diversas funções. Nos ncRNA há que considerar diversos tipos , mas para o seu funcionamento há que atender aos aspectos subjacentes ao emparelhamento entre moléculas. O fenómeno do RNA de interferência (RNAi) desencadeado pelos ncRNA (mi/siRNA) revelou que a estabilidade e tradução dos RNA mensageiros (mRNA) e a estrutura da cromatina podem ser reguladas por esses ncRNA nos animais. A biogénese, mecanismos de acção (cisão ou repressão da tradução), tal como a distinção entre miRNA e siRNA vão sendo descobertas correlativamente com a respectiva identificação e especificidade celular. A presença de miRNA específicos no tecido muscular está bem assinalada tal como a sua possível regulação em hipertrofias musculares notáveis em ovinos (Texel). As potencialidades do conhecimento aprofundado dos fenómenos de RNAi e a construção de miRNA exógenos específicos e sua introdução em células, tecidos ou órgãos, antevêm diversas hipóteses biotecnológicas, terapêuticas, produtivas ou preventivas, acauteladas que estejam as muitas implicações envolvidas.
- Alguns aspectos funcionais do epigenoma, genoma e transcriptoma nos animaisPublication . Dias Correia, José Henrique Rocha; Dias Correia, António AgostinhoO estudo epigenetico das mudanças na expressão dos genes que são hereditárias e que não envolvem uma mutação, deu novas perspectivas aos fenómenos da hereditariedade. Os mecanismos epigeneticos tais como a metilação ou as modificações covalentes das histonas e os RNA de interferência estão envolvidos em toda esta problemática. Neste âmbito os diferentes estados de metilação das citosinas do DNA modelam uma série de processos biológicos. Por outro lado as alterações epigeneticas ocorridas inclusive desencadeadas pelo meio envolvente podem levar á transmissão hereditária dessas novas características. O conhecimento da sequencia total dos genomas de algumas espécies animais permitiu, através de diversas metodologias, averiguar a sua operacionalidade inclusive de uma e de outra cadeia do DNA e as suas nuances de transcrição consoante as células, tecidos, órgãos, factores envolventes, etc. Foi assim possível conhecer muito mais profundamente os transcriptomas correspondentes ao conjunto total de genes transcritos e começar a perceber as formas como podem ser regulados os diversíssimos genes codificadores de proteínas ou não codificadores de proteínas mas activos, condicionando e orquestrando todo o funcionamento da maquina biológica.
- Cytokines and neutrophil extracellular traps in the equine endometrium: friends or foes?Publication . Galvão, António; Rebordão, Maria Rosa; Szóstek, Anna Z.; J. Skarzynski, Dariusz; Ferreira-Dias, GraçaCytokines may play a dual role in the reproductive tract – either involved in physiologic processes or mediating inflammation and other pathologic processes. Physiologic secretory and angiogenic function in the equine endometrium appears to be regulated by cytokines TNFa, FasL, IFNg through their receptors. These receptors are present in glandular epithelium, and stroma cells and their mRNA expression changes throughout the estrous cycle. Besides, interleukins (IL-1a and IL-1b) and their receptors mRNA expression vary according to various degrees of endometrium inflammation (endometritis) and fibrosis (endometrosis). A novel paradigm in innate immunity and neutrophils (PMN) hyperactivation is PMN ability to cast out their DNA in response to infectious stimuli. These PMN extracellular traps (NETs) bind and kill pathogens, at the infection site. The intriguing dilemma is that even though NETs may function as a first line of defense, they also release molecules that may contribute to tissue damage. Thus, we postulate that PMN present in the endometrium at estrus, mating or infection, might form NETs, and release nucleic and cytoplasmic proteins with immunomodulatory properties. Equine PMN stimulated in vitro showed NETs formation capacity when in contact with some bacteria strains obtained from mares with endometritis, such as Streptococcus zooepidemicus, Escherichia coli and Staphylococus capitis. In this regard, even though NETs and cytokines function as an effective antimicrobial first line of defense or modulate physiologic endometrial function, respectively (friends), they may also be involved in endometrial fibrosis pathogenesis and endometrial secretory function impairment, due to enhanced NETs formation and/or a decrease on NETs degradation (foes).
- Cytokines and angiogenesis in the corpus luteumPublication . Galvão, António M.; Ferreira-Dias, Graça; Skarzynski, Dariusz J.In adults, physiological angiogenesis is a rare event, with few exceptions as the vasculogenesis needed for tissue growth and function in female reproductive organs. Particularly in the corpus luteum(CL), regulation of angiogenic process seems to be tightly controlled by opposite actions resultant fromthe balance between pro- and antiangiogenic factors. It is the extremely rapid sequence of events that determines the dramatic changes on vascular and nonvascular structures, qualifying the CL as a great model for angiogenesis studies. Using the mare CL as a model, reports on locally produced cytokines, such as tumor necrosis factor α (TNF), interferon gamma (IFNG), or Fas ligand (FASL), pointed out their role on angiogenic activity modulation throughout the luteal phase.Thus, the main purpose of this review is to highlight the interaction between immune, endothelial, and luteal steroidogenic cells, regarding vascular dynamics/changes during establishment and regression of the equine CL.
- Heterosis for meat quality and fatty acid profiles in crosses among Bos indicus and Bos taurus finished on pasture or grainPublication . Gama, L.T.; Bressan, M.C.; Rodrigues, E.C.; Rossato, L.V.; Moreira, O.C.; Alves, S.P.; Bessa, R.J.B.Physicochemical properties and fatty acid profiles of meat from Bos indicus, Bos taurus and crossbred B. taurus× B. indicus bullocks (n=216), finished on pasture or grain, were used to estimate the effects of heterosis. Meat quality and fatty acid profiles generally benefitedwith crossbreeding, but the advantages from heterosis differed among finishing systems. The Warner–Bratzler shear-force in fresh and aged meat was reduced due to heterosis in pasture-finishing, but the effect was minor under grain-finishing. With pasture-finishing, heterosis caused an increase of 5% in CLA concentration, but few other changes in fatty acid profiles. In grain-finishing, heterosis caused a reduction in intramuscular fat and cholesterol, increased amounts of PUFA, n−6 fatty acids and PUFA/SFA ratio, and a decline in atherogenic index. The Δ9 desaturase estimated activity in crossbreds showed a behavior close to B. indicus, suggesting the existence of few loci and a dominance genetic effect on enzymes involved in fatty acid synthesis and metabolism.
- Small angle X-ray scattering analysis of Clostridium thermocellum cellulosome N-terminal complexes reveals a highly dynamic structurePublication . Currie, Mark A.; Cameron, Kate; Dias, Fernando M. V.; Spencer, Holly L.; Bayer, Edward A.; Fontes, Carlos M. G. A.; Smith, Steven P.; Jia, ZongchaoClostridium thermocellum produces the prototypical cellulosome, a large multienzyme complex that efficiently hydrolyzes plant cell wall polysaccharides into fermentable sugars. This ability has garnered great interest in its potential application in biofuel production. The core non-catalytic scaffoldin subunit, CipA, bears nine type I cohesin modules that interact with the type I dockerin modules of secreted hydrolytic enzymes and promotes catalytic synergy. Because the large size and flexibility of the cellulosome preclude structural determination by traditional means, the structural basis of this synergy remains unclear. Small angle x-ray scattering has been successfully applied to the study of flexible proteins. Here, we used small angle x-ray scattering to determine the solution structure and to analyze the conformational flexibility of two overlapping N-terminal cellulosomal scaffoldin fragments comprising two type I cohesin modules and the cellulose-specific carbohydrate-binding module from CipA in complex with Cel8A cellulases. The pair distribution functions, ab initio envelopes, and rigid body models generated for these two complexes reveal extended structures. These two N-terminal cellulosomal fragments are highly dynamic and display no preference for extended or compact conformations. Overall, our work reveals structural and dynamic features of the N terminus of the CipA scaffoldin that may aid in cellulosome substrate recognition and binding.
- Assessing carcass and meat characteristics of Damara, Dorper and Australian Merino lambs under restricted feedingPublication . Almeida, André M.; Kilminster, Tanya; Scanlon, Tim; Araújo, Susana S.; Milton, John; Oldham, Chris; Greeff, Johan C.Seasonal weight loss (SWL) is the most pressing constraint in ruminant production systems in tropical climates. SWL is controlled using supplementation, which is costly and difficult to implement in extensive systems, or using breeds adapted to tropical hot dry climates, like the Damara and Dorper. Albeit 15 years in Australia, little is known on how these sheep compare to Australian Merino. Here, the responses of the Damara, Dorper and Merino breeds to nutritional stress were compared. Seventy-two 6-month-old ram lambs, 24 from each breed, were allocated to growth (gaining 100 g/day) or restricted diets (losing 100 g/day, 85 % of maintenance needs). Animals were weighed and carcass and meat characteristics determined. Results point out to the existence of important differences between the three genotypes, in particular between the Merino and the Southern African breeds. Additionally, Merino ram lambs seem to have been more influenced by SWL than the other two, with consequences on meat characteristics.
- Understanding regeneration through proteomicsPublication . Franco, Catarina; Soares, Renata; Pires, Elisabete; Koci, Kamila; Almeida, André M.; Santos, Romana; Coelho, Ana VarelaRegeneration is a complex cellular process that, rather than simply forming a scar following injury, the animal forms a new functional tissue. Regeneration is a widespread process among metazoa, although not uniformly. Planaria, starfish, and some worms can regenerate most of their body, whereas many other species can only regenerate parts of specific tissues or fail to accomplish a functional regrowth, as is the case of mammals CNS. Research in regenerative medicine will possibly culminate in the regeneration of organs/tissues originally not prone to this process. Despite the complexity of the interactions and regulatory systems involved, the variety of tissues and organs these cells differentiate into has so far impaired the success of direct transplantation to restore damaged tissues. For this reason, a study, at the molecular level of the regeneration mechanisms developed by different animal models is likely to provide answers to why these processes are not readily activated in mammals. Proteomic-based approaches are being recognized as extremely useful to study of regeneration events, also because there is a relevant contribution of posttranscriptional processes that involve frequently the occurrence of a broad range of PTMs. The present review focuses on the significant knowledge brought up by proteomics in diverse aspects of regeneration research on different animal models, tissues, and organs.
- Carcass fat partitioning and meat quality of Alentejana and Barrosã young bulls fed high or low maize silage dietsPublication . Costa, Ana S. H.; Costa, Paulo; Bessa, Rui J. B.; Lemos, José P. C.; Simões, Jorge A.; Silva, José Santos; Fontes, Carlos M. G. A.; Prates, José A. M.This study assessed the effect of breed and diet on carcass composition, particularly fat partitioning, and meat quality in young bulls. An experiment with forty young bulls from two phylogenetically distant Portuguese bovine breeds, Alentejana and Barrosã, fed two diets with different maize silage to concentrate ratios, but isoenergetic and isonitrogenous, was carried out until the animals reached 18 months of age. In the longissimus lumborum muscle, Barrosã bulls fed the low silage diet had the highest intramuscular fat (IMF) content. Bulls fed the low silage diet also had the highest IMF content in the semitendinosus muscle. Diet determined the proportions of total visceral fat and individual fat depots. Under these experimental conditions, it was shown that the genetic background is a major determinant of carcass composition and meat quality, and that the dietary differences studied had limited effect on carcass composition.
- An application of wavelet analysis to meat consumption cyclesPublication . Banovic, Marija; Nunes, Luis Catela; Arsenijevic, VladanThe existence or nonexistence of changes in meat consumption cycles is critical to meat industry. If the change is existent, there is a need to understand what motivates the change to identify the most appropriate response. Wavelet analysis is considered here as a promising technique that may lead to a better understanding of characteristic patterns and changes in the meat consumption cycles.