Biology subjects

Almeida, F.

Publications and source records attributed to Almeida, F..

13 recordsLinked to original sources

bioRxiv2025

Cross-Species Communication via Fungal Extracellular Vesicles

Extracellular vesicles (EVs) play crucial roles in fungal communication and host immune modulation, representing potential therapeutic targets for fungal infections. This study investigated the role of fungal EVs in both intra- and interspecies communication, focusing on their effects on virulence and immune responses. Co-incubation experiments were performed using EVs derived from Candida albicans and Candida auris to assess interactions with C. albicans planktonic cells and biofilms, as well as Cryptococcus neoformans and Cryptococcus gattii EVs interacting with C. neoformans cultures. EVs were observed associating with recipient cell surfaces, suggesting subsequent internalization. Functional assays revealed that EV exposure led to increased expression of Cap59, Lac1, Ure1, and Erg11 genes, correlating with reduced antifungal susceptibility in both planktonic and biofilm forms. Additionally, EVs facilitated cross-species communication, enhancing biofilm adhesion and dispersion, which underscores their role in phenotypic modulation. Macrophages stimulated with fungal EVs exhibited receptor-specific gene expression changes, notably the upregulation of galectin-3, along with a pro-inflammatory phenotype marked by increased iNOS expression and elevated cytokine levels (IL-1{beta}, IL-6, and IL-8). Collectively, these findings underscore a critical role for fungal EVs in interspecies communication, biofilm regulation, and immune modulation, offering valuable insights into fungal pathogenicity mechanisms. ImportanceCurrently, no vaccines exist to prevent fungal infections, underscoring the need for new therapies. As fungal diseases increase globally, understanding fungal biology is essential to identifying treatment targets. Fungi use EVs to communicate and evade immune responses. EVs mediate cell-cell communication, transporting proteins, polysaccharides, lipids, and nucleic acids - serving as "messages" exchanged within a fungal network. Understanding how these vesicles facilitate communication not only within a single species but also across different fungal species can shed light on their contribution to infection persistence and cross-species adaptability. Moreover, EVs may have a broader role in inter-kingdom communication, influencing how fungi interact with host immune cells. The impact of fungal EVs on human innate immune responses remains a largely underexplored area, with significant gaps in our knowledge. This study aims to examine how fungal EVs affect immune responses and whether their signaling varies across species, potentially revealing new therapeutic targets.

microbiology↗

bioRxiv2024

Optimizing Lipidomics Analysis Workflows for Biological Fluids and Extracellular Vesicles with Integrated Liquid Chromatography Tandem Mass Spectrometry Approaches

Lipidomics, a subfield of metabolomics, involves the comprehensive analysis of lipids within biological systems and has become a cornerstone of biomedical research, driven by recent technological advancements. Lipids are crucial biomolecules in cellular functions and have been increasingly recognized for their roles in physiological and pathological processes. This study focuses on innovative strategies for developing, validating, and applying comprehensive analytical methods for untargeted lipidomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in human plasma and extracellular vesicles (EVs). We describe improvements based on analytical validation parameters, including inter-day repeatability, limit of quantification, precision, accuracy, recovery, and matrix effects. Plasma samples were used as a proof-of-concept study, and the method was ultimately applied to human macrophage-derived EVs. Samples preparations were achieved through four liquid-liquid extraction methods for lipids in order to achieve a broad coverage of lipid classes as well as high recovery and repeatability. Additionally, we demonstrated that a sonication-assisted homogenization step effectively facilitates lipid extraction from EVs. Through untargeted lipidomics, our study identifies and quantifies a diverse range of lipid species in human plasma (225 molecular lipids) and macrophage-derived EVs (124 molecular lipids) within different classes. Overall, we present an innovative methodology that combines pre-analytical lipid extraction techniques with high-resolution LC-MS/MS to enhance lipidomics research. This approach holds promise for personalized medicine and the discovery of novel lipid cargo associated with the various biological pathways involved with EVs biogenesis.

biochemistry↗

bioRxiv2024

Deciphering Cargo Contents in Extracellular Vesicles of Candida haemulonii var. vulnera

ABSTRACTCandida haemulonii comprises a group of pathogenic fungi known for their resistance to primary antifungal treatments. Infections caused by these pathogens present substantial challenges due to the difficulties in accurate identification. Extracellular vesicles (EVs) released by these fungi play a critical role in the pathogen-host interaction, potentially influencing antifungal resistance and virulence. Previous research by our group indicates that EVs contain immunogenic particles capable of impacting the hosts immune response. Understanding the composition of these EVs is crucial for elucidating the mechanisms underlying resistance and virulence in C. haemulonii var. vulnera. This study aims to investigate the contents of EVs from C. haemulonii var. vulnera using proteomic and microRNA sequencing tools, providing insights into their role in adaptation, survival, and the progression of infections. Our findings reveal key proteins transported by EVs, including BMH1, TEF1, CDC19, and PDC11. These proteins are involved in various cellular processes, such as the alteration of cell wall structure, biofilm formation, and facilitation of morphological changes, among others. Additionally, we observed that miRNA-like molecules transported within EVs are linked to the electron transport chain and regulation of the citric acid cycle, which are metabolic processes associated with virulence factors and rapid adaptation to diverse hosts or environments. In this context, our findings provide a novel perspective on fungal EVs, highlighting their potential as targets for therapies. Therefore, these vesicles may reflect the expression levels of regulatory molecules crucial for the survival, pathogenicity, and virulence of C. haemulonii var. vulnera. IMPORTANCEThe study of Candida haemulonii complex holds substantial clinical significance due to its notable resistance to conventional antifungal therapies and the complex challenges inherent in its specific identification. This research focuses on cargo of EVs released by these fungi, which play an essential role in pathogen-host interactions, influencing fungal pathogenicity. EVs contain immunogenic particles that can modulate the hosts immune response. Proteomic and microRNA analyses of EVs from Candida haemulonii var. vulnera have identified key proteins and miRNAs involved in cellular processes such as metabolic adjustment, biofilm formation, and modulation of cytoplasmic functions. These components are essential for the adaptation, survival, and progression of infections. This study offers novel insights into fungal EVs, underscoring their potential as targets for therapeutic intervention. By elucidating the mechanisms underlying the rapid adaptation of Candida haemulonii, the research enhances our understanding of the pathogenicity of this emerging yeast.

microbiology↗

bioRxiv2024

Extracellular vesicles produced during fungal infection in humans are immunologically active

Of the known 1.5 million fungal species, Candida spp., Cryptococcus spp., and Paracoccidioides spp. are the main pathogenic species causing serious diseases with almost two million annual deaths. The diagnosis and treatment of fungal infections are challenging since of the limited access to diagnostic tests and the emergence of antifungal resistance. Extracellular vesicles (EVs) promote the interactions of fungal cells with other organisms and play an important role in the pathogen-host relationship. Owing to the complexity of fungal EVs and the lack of clinical studies on their roles in human infections, we studied the EVs from the serum and urine samples of patients with fungal infections caused by Candida albicans, Cryptococcus neoformans, and Paracoccidioides brasiliensis and determined their roles. Steroids, sphingolipids, and fatty acids were identified as the main secondary metabolites via mass spectrometry analysis. We asked whether these metabolites in EVs could play roles in modulating the host immune response. Our findings revealed the polarization of the proinflammatory profile in murine and human macrophages, with the increased production of cytokines, such as the tumor necrosis factor-, interferon-{gamma}, and interleukin-6, and an increased expression of the inducible nitric oxide synthase gene, a M1 response marker. Therefore, circulating EVs from patients with fungal infections are likely involved in the disease pathophysiology. Our findings provide insights into the roles of EVs in fungal infections in clinical samples and in vitro, suggesting possible targets for systemic mycoses therapy. Significance StatementFungal infections cause approximately 1.6 million deaths annually. Due to therapeutic and diagnostic limitations, it is mandatory to understand and develop new immunological interventions. Despite several in vitro studies on the production of extracellular vesicles (EVs) from fungal pathogens, this study is a pioneer in the identification and characterization of EVs in the course of fungal infection in humans. Our group demonstrated the presence of EVs in clinical samples from patients diagnosed with candidiasis, cryptococcosis, and paracoccidioidomycosis, as well as the EVs interaction produced by host and fungal pathogen with the immune system, resulting in relationships that may be beneficial for the progression or elimination of fungal disease.

microbiology↗

bioRxiv2023

Deacetylation by sirtuins is important for Aspergillus fumigatus pathogenesis and virulence

Protein acetylation is a crucial post-translational modification that controls gene expression and a variety of biological processes. Sirtuins, a prominent class of NAD+-dependent lysine deacetylases, serve as key regulators of protein acetylation and gene expression in eukaryotes. In this study, six single knockout strains of fungal pathogen Aspergillus fumigatus were constructed, in addition to a strain lacking all predicted sirtuins (SIRTKO). Phenotypic assays suggest that sirtuins are involved in cell wall integrity, secondary metabolite production, thermotolerance, and virulence. AfsirE deletion resulted in attenuation of virulence, as demonstrated in murine and Galleria infection models. The absence of AfSirE leads to altered acetylation status of proteins, including histones and non-histones, resulting in significant changes in the expression of genes associated with secondary metabolism, cell wall biosynthesis, and virulence factors. These findings encourage testing sirtuin inhibitors as potential therapeutic strategies to combat A. fumigatus infections or in combination therapy with available antifungals.

microbiology↗

bioRxiv2021

Aspergillus fumigatus acetate utilisation impacts virulence traits and pathogenicity

Aspergillus fumigatus is a major opportunistic fungal pathogen of immunocompromised and immunocompetent hosts. To successfully establish an infection, A. fumigatus needs to use host carbon sources, such as acetate, present in the body fluids and peripheral tissues. However, utilisation of acetate as a carbon source by fungi in the context of infection has not been investigated. This work shows that acetate is metabolised via different pathways in A. fumigatus and that acetate utilisation is under the regulatory control of a transcription factor (TF), FacB. A. fumigatus acetate utilisation is subject to carbon catabolite repression (CCR), although this is only partially dependent on the TF and main regulator of CCR CreA. The available extracellular carbon source, in this case glucose and acetate, significantly affected A. fumigatus virulence traits such as secondary metabolite secretion and cell wall composition, with the latter having consequences for resistance to oxidative stress, to anti-fungal drugs and to human neutrophil-mediated killing. Furthermore, deletion of facB significantly impaired the in vivo virulence of A. fumigatus in both insect and mammalian models of invasive aspergillosis. This is the first report on acetate utilisation in A. fumigatus and this work further highlights the importance of available host-specific carbon sources in shaping fungal virulence traits and subsequent disease outcome, and a potential target for the development of anti-fungal strategies. ImportanceAspergillus fumigatus is an opportunistic fungal pathogen in humans. During infection, A. fumigatus is predicted to use host carbon sources, such as acetate, present in body fluids and peripheral tissues, to sustain growth and promote colonisation and invasion. This work shows that A. fumigatus metabolises acetate via different pathways, a process that is dependent on the transcription factor FacB. Furthermore, the type and concentration of the extracellular available carbon source were determined to shape A. fumigatus virulence determinants such as secondary metabolite secretion and cell wall composition. Subsequently, interactions with immune cells are altered in a carbon source-specific manner. FacB is required for A. fumigatus in vivo virulence in both insect and mammalian models of invasive aspergillosis. This is the first report that characterises acetate utilisation in A. fumigatus and highlights the importance of available host-specific carbon sources in shaping virulence traits and potentially subsequent disease outcome.

microbiology↗

bioRxiv2021

Fungal extracellular vesicles are involved in intraspecies intracellular communication

Fungal infections are associated with high mortality rates in humans. The risk of fungal diseases creates the urgent need to broaden the knowledge base regarding their pathophysiology. In this sense, the role of extracellular vesicles (EVs) has been described to convey biological information and participate in the fungal-host interaction process. EVs play many roles, including cellular physiology, responding to environmental cues, mediating a complex circuit of cellular communication in bidirectional crosstalk with other organisms, and the communication between fungal cells has been speculated. This study demonstrated the intra species uptake of EVs in fungi, including Candida albicans, Aspergillus fumigatus, and Paracoccidioides brasiliensis, and the effects triggered by EVs in fungal cells. In C. albicans, we evaluated the involvement of EVs in yeast to hyphae transition, whilst in P. brasiliensis and A. fumigatus the function of EVs as stress transducers was investigated. Both P. brasiliensis and A. fumigatus were exposed to an inhibitor of glycosylation or UV light, respectively. The results demonstrated the role of EVs in regulating the expression of target genes and phenotype features. The EVs treatment induced cellular proliferation and boosted the transition yeast to hyphal transition in C. albicans, while they enhanced stress signals in A. fumigatus and P. brasiliensis, establishing a role for EVs in fungal intra species communication. Thus, fungal EVs regulate the virulence and adaptive traits in fungal interaction systems as potent message effectors, and understanding their effects and mechanism(s) of action could be exploited in antifungal therapies. Author SummaryExtracellular vesicles (EVs) play an important role in export systems. They act as vehicles for the transference of complex cargoes with broad biological functions, such as proteins, carbohydrates, pigments, nucleic acids, and lipids. EVs can contribute to fungal infection outcomes. The EV content exerts immunomodulatory functions during fungus-host interactions. Furthermore, the participation of EVs in communication between fungal cells has been speculated. This study investigated the capacity of EVs to mediate intra-species in three genera of human pathogenic fungi and established a regulatory function of EVs. We also assessed the features of this regulation by analyzing the cellular morphological aspects of fungi after stimulation with EVs. Our data suggest fungal EVs can function as potent signal mediators that mediate virulence and adaptive responses.

microbiology↗

bioRxiv2020

Integrated transcriptional analysis of the cellular and extracellular vesicle RNA content of Candida auris in response to caspofungin

Candida auris has emerged as a serious worldwide threat by causing invasive infections in humans that are frequently resistant to one or more conventional antifungal medications, resulting in high mortality rates. Against this backdrop, health warnings around the world have focused efforts on understanding C. auris fungal biology and effective treatment approaches to combat this fungus. To date, there is little information about C. auris gene expression regulation in response to antifungal treatment. Our integrated analyses focused on the comparative transcriptomics of C. auris in the presence and absence of caspofungin as well as a detailed analysis of the yeasts extracellular vesicle (EV)-RNA composition. The results showed that genes coding oxidative stress response, ribosomal proteins, cell wall, and cell cycle were significantly upregulated in the presence of caspofungin, whereas transcriptional regulators and proteins related to the nucleus were downregulated. The mRNAs in the EVs were associated with stress responses induced by caspofungin and the ncRNA content of the EVs shifted during caspofungin treatment. Altogether, the results provide further insights into the fungal response to caspofungin and demonstrate that analyses of C. auris growth under antifungal stress can elucidate resistance and survival mechanisms of this fungus in response to medical therapy.

molecular biology↗

bioRxiv2020

Aspergillus fumigatus G-protein coupled receptors GprM and GprJ are important for the regulation of the cell wall integrity pathway, secondary metabolite production, and virulence

G-protein coupled receptors (GPCRs) are extracellular signalling receptors that sense environmental cues to coordinate a biological response. Fungi sense their environment primarily through GPCR-mediated signalling pathways, which in turn regulate fungal development, metabolism, virulence and mycotoxin biosynthesis. A. fumigatus is an important human pathogen that causes aspergillosis, a heterogeneous group of diseases that presents a wide range of clinical manifestations. Here, we investigate in detail the role of the GPCRs GprM and GprJ in growth and gene expression. GprM and GprJ are important for melanin production and the regulation of the cell wall integrity (CWI) pathway. Overexpression of gprM and gprJ causes a 20 and 50% reduction in growth rate when compared to the wild-type (WT) strain, and increases sensitivity to cell wall-damaging agents. Phosphorylation of the CWI protein kinase MpkA is increased in the {Delta}gprM and {Delta}gprJ strains and decreased in the overexpression mutants when compared to the WT strain. Furthermore, differences in cell wall polysaccharide concentrations and organization were observed in these strains. RNA-sequencing suggests that GprM and GprJ negatively regulate genes encoding secondary metabolites (SMs). Mass spectrometry analysis confirmed that the production of fumagillin, pyripyropene, fumigaclavine C, fumiquinazoline, and fumitremorgin is reduced in the {Delta}gprM and {Delta}gprJ strains, and that this regulation occurs, at least partially, through the activation of MpkA. Overexpression of grpM also resulted in the regulation of many transcription factors, with AsgA predicted to function downstream of GprM and MpkA signalling. Finally, we show that the {Delta}gprM and {Delta}gprJ mutants are reduced in virulence in the Galleria mellonella insect model of invasive aspergillosis. This work further contributes to unravelling functions of A. fumigatus GPCRs and shows that GprM and GprJ are essential for CWI, secondary metabolite production and virulence. Author summaryA. fumigatus is the main ethiological agent of invasive pulmonary aspergillosis, a life-threatening fungal disease that occurs in severely immuno-compromised humans. Withstanding the host environment is essential for A. fumigatus virulence and sensing of extracellular cues occurs primarily through G-protein coupled receptors (GPCRs) that activate signal transduction pathways, which in turn regulate fungal development, metabolism, virulence and mycotoxin biosynthesis. The A. fumigatus genome encodes 15 putative classical GPCRs, with only three having been functionally characterized to date. In this work, we show that the two GPCRs GprM and GprJ regulate the phosphorylation of the mitogen-activated protein kinase MpkA and thus control the regulation of the cell wall integrity pathway. GprM and GprJ are also involved in the regulation of the production of the secondary metabolites fumagillin, pyripyropene, fumigaclavine C, fumiquinazoline, melanin, and fumitremorgin and this regulation partially occurs through the activation of MpkA. Furthermore, GprM and GprJ are important for virulence in the insect model Galleria mellonella. This work therefore functionally characterizes two GPCRs and shows how they regulate several intracellular pathways that have been shown to be crucial for A. fumigatus virulence.

microbiology↗

bioRxiv2020

Functional characterization of clinical isolates of the opportunistic fungal pathogen Aspergillus nidulans

Aspergillus nidulans is an opportunistic fungal pathogen in patients with immunodeficiency and virulence of A. nidulans isolates has mainly been studied in the context of the chronic granulomatous disease (CGD), with characterization of clinical isolates obtained from non-CGD patients remaining elusive. This study therefore carried out a detailed biological characterization of two A. nidulans clinical isolates (CIs), obtained from a patient with breast carcinoma and pneumonia and from a patient with cystic fibrosis that underwent lung transplantation, and compared them to the reference, non-clinical A4 strain. Both CIs presented increased growth in comparison to the reference strain in the presence of physiologically-relevant carbon sources. Metabolomic analyses showed that the three strains are metabolically very different from each other in these carbon sources. Furthermore, the CIs were highly susceptible to cell wall perturbing agents but not to other physiologically-relevant stresses. Genome analyses identified several frame-shift variants in genes encoding cell wall integrity (CWI) signalling components. Significant differences in CWI signalling were confirmed by western blotting among the three strains. In vivo virulence studies using several different models revealed that strain MO80069 had significantly higher virulence in hosts with impaired neutrophil function when compared to the other strains. In summary, this study presents detailed biological characterization of two A. nidulans sensu stricto clinical isolates. Just like in A. fumigatus, strain heterogeneity exists in A. nidulans clinical strains that can define virulence traits. Further studies are required to fully characterize A. nidulans strain-specific virulence traits and pathogenicity. ImportanceImmunocompromised patients are susceptible to infections with opportunistic filamentous fungi from the genus Aspergillus. Although A. fumigatus is the main etiological agent of Aspergillus spp.-related infections, other species, such as A. nidulans are prevalent in a condition-specific manner. A. nidulans is a predominant infective agent in patients suffering from chronic granulomatous disease (CGD). A. nidulans isolates have mainly been studied in the context of CGD, although infection with A. nidulans also occurs in non-CGD patients. This study carried out a detailed biological characterization of two non-CGD A. nidulans clinical isolates and compared it to a reference strain. Phenotypic, metabolomic and genomic analyses highlight fundamental differences in carbon source utilization, stress responses and maintenance of cell wall integrity among the strains. One clinical strain had increased virulence in models with impaired neutrophil function. Just as in A. fumigatus, strain heterogeneity exists in A. nidulans clinical strains that can define virulence traits.

microbiology↗

bioRxiv2019

What does mitogenomics tell us about the evolutionary history of the Drosophila buzzatii cluster (repleta group)

The Drosophila repleta group is an array of more than 100 cactophilic species endemic to the \"New World\". The acquisition of the ability to utilize decaying cactus tissues as breeding and feeding sites is a key aspect that allowed the successful diversification of the repleta group in the American deserts. Within this group, the Drosophila buzzatii cluster is a South American clade of seven cactophilic closely related species in different stages of divergence, a feature that makes it a valuable model system for evolutionary research. However, even though substantial effort has been devoted to elucidating the phylogenetic relationships among members of the D. buzzatii cluster, the issue is still controversial. In effect, molecular phylogenetic studies performed to date generated ambiguous results since tree topologies depend on the kind of molecular marker employed. Curiously, even though mitochondrial DNA has become a popular marker in evolutionary biology and population genetics, none of the more than twenty Drosophila mitogenomes assembled so far belongs to this cluster. In this work we report the assembly of six complete mitogenomes of five species: D. antonietae, D. borborema, D. buzzatii, D. seriema and two strains of D. koepferae, with the aim to revisit the phylogenetic relationships and divergence times by means of a mitogenomic approach. The recovered topology using complete mitogenomes gives support to the hypothesis of the monophyly of that the D. buzzatii cluster and shows two main clades, one including D. buzzatii and D. koepferae (both strains) and the other the remaining species. These results are in agreement with previous reports based on a few mitochondrial and/or nuclear genes but in conflict with the results of a recent large-scale nuclear phylogeny, suggesting that nuclear and mitochondrial genomes depict different evolutionary histories.

evolutionary biology↗

bioRxiv2019

Galectin-3 inhibits Paracoccidioides brasiliensis growth and impacts paracoccidioidomycosis through multiple mechanisms

The thermodimorphic pathogenic fungi Paracoccidioides brasiliensis and Paracoccioidioides lutzii are the etiologic causes of paracoccidioidomycosis (PCM), the most prevalent systemic mycosis in Latin America. Galectin-3 (Gal-3), an animal {beta}-galactoside-binding protein, modulates important roles during microbial infections, such as triggering a Th2-polarized immune response in PCM. Herein, we demonstrate that Gal-3 also plays other important roles in P. brasiliensis infection. We verified Gal-3 levels are upregulated in human and mice infections and establish that Gal-3 inhibits P. brasiliensis growth by inhibiting budding. Furthermore, Gal-3 affects disruption and internalization of extracellular vesicles (EV) from P. brasiliensis by macrophages. Our results suggest important roles for Gal-3 in P. brasiliensis infection, indicating that increased Gal-3 production during P. brasiliensis infection may account for affecting the fungal growth and EV stability, promoting a benefic course of experimental PCM. IMPORTANCEParacoccidiodomycosis (PCM) is the most prevalent systemic mycosis in Latin America. Although the immune mechanisms to control PCM are still not fully understood, several events of the host innate and adaptive immunity are crucial to determine the progress of the infection. Mammalian {beta}-galactoside-binding protein Galectin-3 (Gal-3) plays significant roles during microbial infections, and has been studied for its immunomodulatory roles but it can also have direct antimicrobial effects. We asked whether this protein plays a role in P. brasiliensis. We report herein that Gal-3 indeed has direct effects on fungal pathogen, inhibiting fungal growth and reducing extracellular vesicles stability. Our results suggest a direct role for Gal-3 in P. brasiliensis infection, with beneficial effects for the mammalian host.

microbiology↗

bioRxiv2019

Postnatal development of skeletal muscle in IUGR pigs: morphofunctional phenotype and molecular mechanisms

Intrauterine growth restriction (IUGR) is a serious condition which impairs the achievement of the fetus full growth potential and occurs in a natural and severe manner in pigs. Knowledge on skeletal muscle morphofunctional phenotype and its molecular regulation in IUGR pigs is important to understand postnatal muscle development and may help the establishment of therapies to improve skeletal muscle growth in those individuals. To investigate the impairment of skeletal muscle postnatal development due to IUGR, we evaluated the histomorphometrical pattern of the semitendinosus muscle, the Myosin Heavy Chain (embryonic, I, IIa, IIb and IIx MyHC) fiber composition and the relative expression of genes related to myogenesis, adipogenesis and growth during three specific periods: postnatal myogenesis (newborn to 100 days of age), postnatal development (newborn to 150 days of age), and hypertrophy (100 days to 150 days of age), comparing IUGR and normal birth weight (NW) pigs. Growth restriction in utero affected muscle fiber diameter, total fiber number and muscle cross sectional area which were smaller in IUGR pigs at birth (P < 0.05). Even though the percentage of MyHC-I myofibers was higher in IUGR females at birth (P < 0.05), in older gilts, a lower percentage of MyHC-IIx isoform (P < 0.05) and the presence of emb-MyHC were also observed in that experimental group. Regarding the pattern of gene expression in the postnatal myogenesis period, growth restriction in utero led to a down regulation of myogenic factors, which delayed the expression of signals that induces skeletal muscle myogenesis (PAX7, MYOD, MYOG, MYF5 and DES). Taken together, the muscle morphofunctional aspects described and their ontogenetic regulation define the possible molecular origins of the notorious damage to the postnatal musculature development in IUGR pigs.

cell biology↗