Pedro Rodrigues

University of Porto, Oporto, Porto, Portugal

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Publications (57)170.11 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The adult monorchiid, Postmonorcheides maclovini (Szidat, 1950), digenean parasite of the Patagonian blennie Eleginops maclovinus (Cuvier) (Eleginopidae) from Puerto Deseado (47° 45' S, 65° 55' W), Argentina, was characterized and its life cycle elucidated. P. maclovinus is the only species of the genus Postmonorcheides, proposed by Szidat (1950) from Tierra del Fuego province (~54° S), Argentina. This digenean uses the Patagonian blennie as definitive host, and the intertidal bivalve Lasaea adansoni (Gmelin) (Lasaeidae) as both first and second intermediate host (metacercariae encyst inside sporocysts), being the first record of this clam as intermediate host of trematodes parasites. The cercaria may, in addition to encysting in the sporocyst, emerge and presumably infect other intermediate hosts. This is the second report of a monorchiid species with metacercariae encysting inside the sporocyst. Adults were found parasitizing the fish stomach, pyloric caeca and intestine with a prevalence of 100%; sporocysts with cercariae and/or metacercariae were found parasitizing the gonad of the bivalve with a prevalence of 2.78%. The cercariae possess a well-developed tail and eye-spots are absent. The ITS1 sequence from the adult digeneans found in the Patagonian blennie, identified as P. maclovini, was found to be identical to the ITS1 sequences obtained both from sporocysts containing cercariae and encysted metacercariae found in L. adansoni.
    Parasitology International 09/2015; 65(1). DOI:10.1016/j.parint.2015.09.008 · 1.86 Impact Factor
  • João V Neves · Carolina Caldas · Inês Vieira · Miguel F Ramos · Pedro N S Rodrigues ·
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    ABSTRACT: Teleost fish rely heavily on their innate immunity for an adequate response against pathogens and environmental challenges, with the production of antimicrobial peptides being one of their first lines of defense. Among those is hepcidin, a small cysteine-rich antimicrobial peptide that is also the key regulator of iron metabolism. Although most mammals possess a single hepcidin gene, with a dual role in both iron metabolism regulation and antimicrobial response, many teleost fish present multiple copies of hepcidin, most likely because of genome duplications and positive Darwinian selection, suggesting that different hepcidins may perform different functions. To study the roles of hepcidin in teleost fish, we have isolated and characterized several genes in the European sea bass (Dicentrarchus labrax) and evaluated variations in their expression levels in response to different experimental conditions. Although several hepcidin genes were found, after phylogenetic analysis they could be clustered in two groups: hamp1-like, with a single isoform similar to mammalian hepcidins, and hamp2-like, with several isoforms. Under experimental conditions, hamp1 was upregulated in response to iron overload and infection and downregulated during anemia and hypoxic conditions. Hamp2 did not respond to either iron overload or anemia but was highly upregulated during infection and hypoxia. In addition, Hamp2 synthetic peptides exhibited a clear antimicrobial activity against several bacterial strains in vitro. In conclusion, teleost fish that present two hepcidin types show a degree of subfunctionalization of its functions, with hamp1 more involved in the regulation of iron metabolism and hamp2 mostly performing an antimicrobial role. Copyright © 2015 by The American Association of Immunologists, Inc.
    The Journal of Immunology 08/2015; 195(6). DOI:10.4049/jimmunol.1501153 · 4.92 Impact Factor
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    ABSTRACT: This paper reviews the family Gymnophallidae, recognizing as valid seven genera; four within the subfamily Gymnophallinae: Gymnophallus Odhner, 1900 (syn. Meiogymnophallus Ching, 1965), Paragymnophallus Ching, 1973, Pseudogymnophallus Hoberg, 1981, and Bartolius Cremonte, 2001, and three in the Parvatrematinae: Parvatrema Cable, 1953, Lacunovermis Ching, 1965, and Gymnophalloides Fujita, 1925. Specimens representing one species of each available genus were chosen from those well-described and non controversial species, for which strong morphological information was available, and used for molecular studies (ITS1-5.8S-ITS2-28S rDNA strands were sequenced). The presence or absence of a pars prostatica differentiates between the 2 subfamilies, Gymnophallinae and Parvatrematinae. The characters used to differentiate genera are: location of the ovary (pre-, post- or inter-testicular), size and location of the genital pore (inconspicuous and located at the anterior margin of the ventral sucker, or conspicuous and located at some distance from the anterior margin of ventral sucker), presence of caecal pockets, and presence or absence of ventral pit (a muscular structure which can be either well-developed, similar in size and musculature to the ventral sucker, or be poorly developed). The characters previously used to distinguish among genera that actually should be considered to separate species include: shape of tegument spines (broad, sharp or serrated), presence of lateral projections on the oral sucker (also called papillae or lips), shape of the seminal vesicle (unipartite or bipartite), shape of the prostatic duct (elongate or oval), presence of papillae on the genital pore, shape of the genital atrium (tubular, wide, oval), shape of the vitellaria (follicular in a variable degree, paired or single), shape of the excretory vesicle (V or Y), extension of uterus (restricted to forebody, at hindbody or extending in both). Additionally, some of these characters may vary with the age of worm. The morphological and molecular information obtained in this study provided strong support for recognizing seven valid genera in the family Gymnophallidae. Copyright © 2014. Published by Elsevier Ireland Ltd.
    Parasitology International 12/2014; 64(2). DOI:10.1016/j.parint.2014.12.003 · 1.86 Impact Factor
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    ABSTRACT: Mycobacterium avium causes respiratory disease in susceptible individuals, as well as disseminated infections in immunocompromised hosts, being an important cause of morbidity and mortality among these populations. Current therapies consist of a combination of antibiotics taken for at least six months, with no more than 60% overall clinical success. Furthermore, mycobacterial antibiotic resistance is increasing worldwide, urging the need to develop novel classes of antimicrobial drugs. One potential and interesting alternative strategy is the use of antimicrobial peptides (AMP). These are present in almost all living organisms as part of their immune system, acting as a first barrier against invading pathogens. In this context, we investigated the effect of several lactoferrin-derived AMP against M. avium. Short peptide sequences from both human and bovine lactoferricins, namely hLFcin1-11 and LFcin17-30, as well as variants obtained by specific amino acid substitutions, were evaluated. All tested peptides significantly inhibited the axenic growth of M. avium, the bovine peptides being more active than the human. Arginine residues were found to be crucial for the display of antimycobacterial activity, whereas the all-D amino acid analogue of the bovine sequence displayed the highest mycobactericidal activity. These findings reveal the promising potential of lactoferricins against mycobacteria, thus opening the way for further research on their development and use as a new weapon against mycobacterial infections.
    Antimicrobial Agents and Chemotherapy 04/2014; 58(6). DOI:10.1128/AAC.02728-13 · 4.48 Impact Factor
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    ABSTRACT: Important for both host and pathogen survivals, iron is a key factor in determining the outcome of an infectious process. Iron with-holding, including sequestration inside tissue macrophages, is considered an important strategy to fight infection. However, for intra-macrophagic pathogens, such as Mycobacterium avium, host defence may depend on intracellular iron sequestration mechanisms. Ferritin, the major intracellular iron storage protein, plays a critical role in this process. In the current study, we studied ferritin expression in mouse bone marrow-derived macrophages upon infection with M. avium. We found that H-ferritin is selectively increased in infected macrophages, through an up-regulation of gene transcription. This increase was mediated by the engagement of Toll like receptor-2, and was independent of TNF-alpha or nitric oxide production. The formation of H-rich ferritin proteins and the consequent iron sequestration may be an important part of the panoply of antimicrobial mechanisms of macrophages.
    PLoS ONE 12/2013; 8(12):e82874. DOI:10.1371/journal.pone.0082874 · 3.23 Impact Factor
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    ABSTRACT: The liver, being the major site of iron storage, is particularly exposed to the toxic effects of iron. Transcription factor NRF2 is critical for protecting the liver against disease by activating the transcription of genes encoding detoxification/antioxidant enzymes. We aimed to determine if the NRF2 pathway plays a significant role in the protection against hepatic iron overload. Wild-type and Nrf2(-/-) mouse primary hepatocytes were incubated with ferric ammonium citrate. Wild-type and Nrf2(-/-) mice were fed standard rodent chow or iron-rich diet for 2 weeks, with or without daily injection of the antioxidant mito-TEMPOL. In mouse hepatocytes, iron induced the nuclear translocation of NRF2 and the expression of cytoprotective genes in an NRF2-dependent manner. Moreover, Nrf2(-/-) hepatocytes were highly susceptible to iron-induced cell death. Wild-type and Nrf2(-/-) mice fed iron-rich diet accumulated similar amounts of iron in the liver and were equally able to increase the expression of hepatic hepcidin and ferritin. Nevertheless, in Nrf2-null mice the iron loading resulted in progressive liver injury, ranging from mild confluent necrosis to severe necroinflammatory lesions. Hepatocytic cell death was associated with gross ultrastructural damage to the mitochondria. Notably, liver injury was prevented in iron-fed animals that received mito-TEMPOL. NRF2 protects the mouse liver against the toxicity of dietary iron overload by preventing hepatocytic cell death. We identify NRF2 as a potential modifier of liver disease in iron overload pathology and show the beneficial effect of the antioxidant mito-TEMPOL in a mouse model of dietary iron-induced liver injury.
    Journal of Hepatology 09/2013; 60(2). DOI:10.1016/j.jhep.2013.09.004 · 11.34 Impact Factor
  • J.V. Neves · C.C. Caldas · P.N.S. Rodrigues ·

    Fish &amp Shellfish Immunology 06/2013; 34(6):1668. DOI:10.1016/j.fsi.2013.03.106 · 2.67 Impact Factor
  • Joao Neves · Pedro Rodrigues ·

    American Journal of Hematology 05/2013; 88(5):E149-E149. · 3.80 Impact Factor

  • American Journal of Hematology 05/2013; 88(5):E222-E222. · 3.80 Impact Factor
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    ABSTRACT: The objective of the study described in this article was to characterize the antimicrobial resistance profiles among E. coli strains isolated from cohabitant pets and humans, evaluating the concurrent colonization of pets, owners, and home surfaces by bacteria carrying the same antimicrobial-resistant genes. The authors also intended to assess whether household surfaces and objects could contribute to the within-household antimicrobial-resistant gene diffusion between human and animal cohabitants. A total of 124 E. coli strains were isolated displaying 24 different phenotypic patterns with a remarkable percentage of multiresistant ones. The same resistance patterns were isolated from the dog's urine, mouth, the laundry floor, the refrigerator door, and the dog's food bowl. Some other multiresistant phenotypes, as long as resistant genes, were found repeatedly in different inhabitants and surfaces of the house. Direct, close contact between all the cohabitants and the touch of contaminated household surfaces and objects could be an explanation for these observations.
    Journal of environmental health 02/2013; 75(6):74-81. · 0.96 Impact Factor
  • S. Silva-Gomes · A.G. Santos · C. Caldas · J.V. Neves · P.N. Rodrigues ·

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    ABSTRACT: Abstract Morphological and molecular evidence suggest that specimens formerly described as Lacunovermis sp. from Nacella (Patinigera) spp. (Patellogastropoda: Patellidae) belong to a new species of Gymnophalloides Fujita, 1925. Based on the new information, they are identified as G. nacellae n. sp. The new species differs from Gymnophalloides tokiensis, G. seoi, and G. heardi mainly through the presence of a group of papillae located on the ventral surface between oral and ventral suckers. A detailed morphological study revealed the lack of pars prostatica, a character previously reported in G. seoi, which is why it was formerly placed in the subfamily Gymnophallinae. Molecular information proved that G. nacellae is close to G. seoi, being nestled together with Parvatrema representatives. This molecular information, along with the absence of pars prostatica, allows these 2 genera to be placed in Parvatrematinae. An amended diagnosis of Gymnophalloides is provided. Histological sections of mantle epithelium of the limpet show metacercariae attached by their oral and ventral suckers in a similar manner to G. seoi in its host, the oyster Crassostrea gigas. Tissue reaction includes cells of outer mantle epithelium being stretched by sucker attachment, hemocyte infiltration of connective tissue between mantle epitheliums, and abnormal calcareous deposition on the inner surface of the shell.
    Journal of Parasitology 07/2012; 99(1). DOI:10.1645/GE-2909.1 · 1.23 Impact Factor
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    Ramos M. F · Barandela T · Marques J. F · Neves J. V · Sousa J. A · Saraiva A · Rodrigues P. N ·

    Fish Pathology 01/2012; 47(2):80-82. · 1.06 Impact Factor
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    Susana Pina · Fernanda Russell-Pinto · Pedro Rodrigues ·
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    ABSTRACT: Maritrema portucalensis sp. nov. (Digenea, Microphallidae) from Aveiro estuary, northern Portugal, is described on the basis of excysted metacercariae obtained from the gill lamellae of the shore crab Carcinus maenas (L.). M. portucalensis sp. nov. most closely resembles Maritrema subdolum Jägerskiöld, 1909, a species that also frequently uses C. maenas as second intermediate host. The new species differs from M. subdolum in having a narrower body at the level of testes and a smaller ovary and testes. Also, the digestive caeca presented various folds along their length, thickening in the terminal region. Moreover, the body surface was fully covered by tegumental spines provided with several teeth. To complement our morphological characterization and to identify M. portucalensis metacercariae, the ITS1 rDNA region of the cysts isolated from C. maenas was sequenced and compared with the corresponding available sequences of digenean trematodes belonging to the family Microphallidae. Alignments revealed 28 base-pair differences between the query-ITS1 and that of M. subdolum, and more importantly a 100% similarity with the sequence of Microphallidae sp. no. 15 cercaria from the snail Hydrobia ulvae. The last observation allowed us to establish an unequivocal association between cercaria known as Microphallidae sp. no. 15, and the metacercaria of M. portucalensis sp. nov. characterized in this work, contributing decisively to the clarification of its life cycle.
    Acta Parasitologica 12/2011; 56(4). DOI:10.2478/s11686-011-0068-0 · 0.91 Impact Factor
  • J.V. Neves · C Caldas · J.M. Wilson · P.N.S. Rodrigues ·
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    ABSTRACT: Hepcidin, an antimicrobial peptide described as a key regulator of iron metabolism, is known to respond in mammals to several stimuli, including iron overload, anemia, hypoxia and inflammation, through a number of molecular pathways. In order to understand the molecular pathways involved in the regulation of hepcidin expression in teleost fish, we have isolated for European sea bass (Dicentrarchus labrax) several coding sequences of known molecules involved on these pathways in mammals, namely jak3, stat3, tmprss6, bmp6, bmpr2, hjv, smad4, smad5, tfr1 and tfr2. The transcription levels of the isolated genes were evaluated by real-time PCR on fish subjected to experimental iron modulation (overload/deficiency) or infection with Photobacterium damsela. Results show that genes associated with the major pathway of the inflammatory response (IL6/JAK/STAT pathway) in mammals are also modulated in sea bass, being up-regulated during infection. Similarly, genes of the pathways classically associated with the response to variations in iron status (the HJV/BMP/SMAD and HFE/TfR pathways) are also modulated, mostly through down-regulation in iron deficiency and up-regulation during iron overload. Interestingly, many of these genes are also found to be up-regulated during infection, which may indicate a crosstalk between the known pathways of hepcidin regulation. These observations suggest the evolutionary conservation of the mechanisms of hepcidin regulation in teleost fish.
    Fish &amp Shellfish Immunology 12/2011; 31(6):1154-61. DOI:10.1016/j.fsi.2011.10.006 · 2.67 Impact Factor
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    ABSTRACT: The morphology, ultrastructure, genetics, and morphometrics of a species of Diplostomum von Nordmann 1832 (Digenea: Diplostomidae), isolated from the European flounder (Platichthys flesus (L.)) caught off the northwest coast of Portugal, are characterized. The metacercarial stage was found unencysted in the lens capsule of the eye. Light microscopical observations revealed the existence of some variability in specimen shape and size, with two morphotypes, referred to as "round" and "long", being apparent. Scanning electron microscopy revealed a smooth, unarmed tegument, with the lappet region being the most irregular and porose. Both the oral and ventral suckers were provided with a series of papillae, which presented very distinctive ultrastructural features and were particularly conspicuous in the case of the ventral sucker. The two morphotypes detected were found to have 100% genetic correspondence in the 18S + ITS1 + 5.8S region of the rDNA. Since the genetic data for this metacercaria differed from those of the species of Diplostomum available in GenBank, a description of a new genotype (accession number GQ370809) is provided. The molecular phylogenetic analyses, in conjunction with principal components and cluster analyses based on morphometric data, revealed the existence of consistent differences between the Diplostomum sp. metacercariae from flounder compared with Diplostomum spathaceum, Diplostomum mergi, Diplostomum pseudospathaceum, and Diplostomum paracaudum. The latter of these species was found to be the most similar to the present material. Our results do not support an evolutionary separation of the European and North American species of Diplostomum.
    Parasitology Research 05/2011; 110(1):81-93. DOI:10.1007/s00436-011-2453-x · 2.10 Impact Factor
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    ABSTRACT: Ammonia is a toxic by-product of amino acid catabolism and a common environmental pollutant that has been associated with increased disease susceptibility in fish although the mechanism is not well understood. We addressed the hypothesis that elevated environmental ammonia acts by impairing the acute phase response (APR). Specifically, we determined the impact of sub-lethal acute (24 h) and chronic (14 d) ammonia exposure on acute phase protein gene expression in zebrafish (Danio rerio) in response to a challenge with bacterial lipopolysaccharide (LPS: i.p. 10 μg/g after 24h). A panel of LPS-responsive genes (SAA, HAMP, LECT2, Hp and IL1β) were identified and evaluated by real-time quantitative PCR. Ammonia was found to impair induction of SAA, HAMP and LECT2 by 50-90%. Both short (15 min, 1h and 24h) and long-term (14 days) exposure to high environmental ammonia concentrations significantly elevated whole-body cortisol levels compared with control fish. Our results reveal for the first time that exposure to high environmental levels of ammonia suppresses the innate immune response in fish. We hypothesize that high environmental ammonia-mediated elevation of cortisol levels in zebrafish may be playing a key role in this immunosuppression, while the mechanisms involved remains to be elucidated.
    Developmental and comparative immunology 05/2011; 36(2):279-88. DOI:10.1016/j.dci.2011.04.008 · 2.82 Impact Factor
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    ABSTRACT: Anaemia is a frequent complication of chronic infectious diseases but the exact mechanisms by which it develops remain to be clarified. In the present work, we used a mouse model of mycobacterial infection to study molecular alterations of iron metabolism induced by infection. We show that four weeks after infection with Mycobacterium avium BALB/c mice exhibited a moderate anaemia, which was not accompanied by an increase on hepatic hepcidin mRNA expression. Instead, infected mice presented increased mRNA expression of ferroportin (Slc40a1), ceruloplasmin (Cp), hemopexin (Hpx), heme-oxygenase-1 (Hmox1) and lipocalin-2 (Lcn2). Both the anaemia and the mRNA expression changes of iron-related genes were largely absent in C.D2 mice which bear a functional allele of the Nramp1 gene. Data presented in this work suggest that anaemia due to a chronic mycobacterial infection may develop in the absence of elevated hepcidin expression, is influenced by Nramp1 and may involve lipocalin-2.
    Immunobiology 04/2011; 216(10):1127-34. DOI:10.1016/j.imbio.2011.04.004 · 3.04 Impact Factor
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    ABSTRACT: The SLC11A1/Nramp1 and SLC11A2/Nramp2 genes belong to the SLC11/Nramp family of transmembrane divalent metal transporters, with SLC11A1 being associated with resistance to pathogens and SLC11A2 involved in intestinal iron uptake and transferrin-bound iron transport. Both members of the SLC11 gene family have been clearly identified in tetrapods; however SLC11A1 has never been documented in teleost fish and is believed to have been lost in this lineage during early vertebrate evolution. In the present work we characterized the SLC11 genes in teleosts and evaluated if the roles attributed to mammalian SLC11 genes are assured by other fish specific SLC11 gene members. Two different SLC11 genes were isolated in the European sea bass (Dicentrarchus. labrax), and named slc11a2-α and slc11a2-β, since both were found to be evolutionary closer to tetrapods SLC11A2, through phylogenetic analysis and comparative genomics. Induction of slc11a2-α and slc11a2-β in sea bass, upon iron modulation or exposure to Photobacterium damselae spp. piscicida, was evaluated in in vivo or in vitro experimental models. Overall, slc11a2-α was found to respond only to iron deficiency in the intestine, whereas slc11a2-β was found to respond to iron overload and bacterial infection in several tissues and also in the leukocytes. Our data suggests that despite the absence of slc11a1, its functions have been undertaken by one of the slc11a2 duplicated paralogs in teleost fish in a case of synfunctionalization, being involved in both iron metabolism and response to bacterial infection. This study provides, to our knowledge, the first example of this type of sub-functionalization in iron metabolism genes, illustrating how conserving the various functions of the SLC11 gene family is of crucial evolutionary importance.
    BMC Evolutionary Biology 04/2011; 11(1):106. DOI:10.1186/1471-2148-11-106 · 3.37 Impact Factor
  • Susana Pina · Fernanda Russell-Pinto · Pedro Rodrigues ·
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    ABSTRACT: The present study describes the anatomy and surface topography of the metacercaria of Microphallusprimas (Jägerskiöld, 1909) infecting the shore crab Carcinus maenas (L.) in Aveiro estuary, northern Portugal. The metacercaria species identification resulted from the combined use of morphological and molecular data, particularly the 28S rDNA gene. The metacercariae encysted preferentially in the host's hepatopancreas and also in the gonads. Isolated cysts were present in two distinct forms, spherical and oval, and were shown to be the identical species by the internal transcribed spacer 1 (ITS1) sequence. Chemically excysted metacercariae were studied by light (LM) and scanning electron microscopy (SEM). Their specific characteristics observed include the particular aspect of the vesiculo-prostatic pouch surrounded by a very thin membrane, the presence of a prominent muscular papilla, and an obvious metraterm. The dorsal and ventral tegumental surfaces of the metacercaria were densely packed with similar squamous spines, which decreased in number and size towards the hindbody. The edges of the posterior and ventral face of the body were coated with numerous microvilli, whose function remains unknown. In order to identify the species of metacercariae, we compared a 28S partial rDNA sequence of the two forms of cysts with the same 28S partial region of M. primas available in GenBank. With this comparison, we determined that the sequences had a 100% similarity and therefore belonged to the same species, i.e., M. primas.
    Folia parasitologica 03/2011; 58(1):48-54. DOI:10.14411/fp.2011.005 · 1.15 Impact Factor

Publication Stats

655 Citations
170.11 Total Impact Points


  • 2005-2014
    • University of Porto
      • • Institute for Molecular and Cell Biology
      • • Instituto de Ciências Biomédicas Abel Salazar (ICBAS)
      Oporto, Porto, Portugal
  • 2012
    • Centro Nacional Patagonico
      Madryn, Chubut, Argentina
  • 2001-2012
    • Institute for Molecular and Cell Biology
      Oporto, Porto, Portugal
  • 2002
    • Vancouver General Hospital
      Vancouver, British Columbia, Canada