Alexandre Lobo-da-Cunha

University of Porto, Oporto, Porto, Portugal

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Publications (63)120.46 Total impact

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    Alexandre Lobo-Da-Cunha · A ˆ Ngela Alves · Elsa Oliveira · Gonc¸alo Calado
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    ABSTRACT: The salivary glands of the cephalaspideans Philine quadripartita (Philinidae), Aglaja tricolorata (Aglajidae) and Haminoea navicula (Haminoeidae) were studied by light and electron microscopy to investigate relationships between diet, phylogeny and morphofunctional features of these glands. In herbivores such as H. navicula the posterior end of the long ribbon-shaped salivary glands is attached to the gizzard, whereas in P. quadripartita and A. tricolorata these glands are shorter and their posterior end is unattached. The salivary glands of the carnivorous cephalaspidean P. quadripartita contains three types of secretory cells. Granular mucocytes and vacuolated mucocytes, both secreting acid polysaccharides, were much more abundant than the granular cells secreting proteins associated with neutral polysaccharides. The same cell types were recognized in the salivary glands of H. navicula, but in this species the granular cells are much smaller and even less abundant. The salivary glands of A. tricolorata contain different secretory cells, which were named cells with dense vacuoles, alveolar cells and granular cells. The first two produce proteins and acid polysaccharides, while granular cells contain proteins and neutral polysaccharides. Based on these results and previously published data, it can be said that histologically the salivary glands of the carnivorous cephalaspidean P. quadripartita are much more similar to the salivary glands of herbivorous cephalaspideans (Bulla striata and H. navicula) and other herbivorous euopisthobranchs (Aplysia depilans), than to the salivary glands of aglajids (A. tricolorata and Philinopsis depicta) in which mucocytes are absent. Thus, having a herbivorous or a carnivorous diet by itself seems not to have been a major driving factor on the histology of salivary glands in cephalaspideans. The digestive system of aglajids differs from that of other carnivorous cephalaspideans, not only in the histology of salivary glands but also in other aspects such as absence of a gizzard, and the lack of a radula in all but one genus. Concerning the morphology of the digestive system, aglajids are highly derived cephalaspideans.
    Full-text · Article · Jan 2016 · Journal of Molluscan Studies
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    ABSTRACT: The exploitation of marine organisms for human nutritional and pharmaceutical purposes has revealed important chemical prototypes for the discovery of new drugs, stimulating compounds isolation and syntheses of new related compounds with biomedical application. Nowadays, it is well known that inflammatory processes are involved in many diseases and the interest in the search for marine natural products with anti-inflammatory potential has been increasing. The genus Aplysia belongs to the class Gastropoda, having a wide geographical distribution and including several species, commonly known as sea hares. Aplysia depilans Gmelin is usually found in the Mediterranean Sea and in the Atlantic Ocean, from West Africa to the French coast. In these marine organisms, most of the digestion and nutrient absorption occurs in the digestive gland. This work aimed to explore the chemical composition and bioactivity of the methanol extract from A. depilans digestive gland. Therefore, fatty acids and carotenoids were determined by GC-MS and HPLC-DAD, respectively. Twenty-two fatty acids and eight carotenoids were identified for the first time in this species. The A. depilans digestive gland revealed to be essentially composed by polyunsaturated fatty acids (PUFA) and xanthophylls. Regarding the anti-inflammatory potential in RAW 264.7 cells stimulated with lipopolysaccharide, it was observed that this matrix has capacity to reduce nitric oxide (NO) and L-citrulline levels, which suggests that its compounds may act by interference with inducible nitric oxide synthase. Taking into account the results obtained, A. depilans digestive gland may be a good source of nutraceuticals, due to their richness in health beneficial nutrients, such as carotenoids and long-chain PUFA.
    Preview · Article · Sep 2015 · Molecules
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    ABSTRACT: An aerobic, Gram-negative rod, designated A2P5T, was isolated from the Douro river, in Porto, Portugal. Cells were catalase- and oxidase-positive. Growth occurred in the range of 15-30 ºC, pH 6-8 and in presence of 1% (w/v) NaCl. The major respiratory quinone was Q8, the genomic DNA had a G+C content estimated to be 47±1 mol% and phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol were amongst the major polar lipids. On basis of the 16S rRNA gene sequence analysis, strain A2P5T was observed to be a member of the family Burkholderiaceae, but could not be identified as member of any validly named genus. The low levels of 16S rRNA gene sequence similarity to other recognized taxa (< 91%), together with the comparative analysis of phenotypic and chemotaxonomic characteristics supported the proposal of a new genus within the family Burkholderiaceae. The name Hydromonas duriensis gen. nov., sp. nov. represented by the type strain of the genus and of the species is the strain A2P5T (= LMG 28428T = CCUG 66137T), is proposed.
    No preview · Article · Aug 2015 · International Journal of Systematic and Evolutionary Microbiology
  • Alexandre Lobo-da-Cunha · Elsa Oliveira · Ângela Alves · Gonçalo Calado · Fernanda Guimarães

    No preview · Article · Aug 2015 · Microscopy and Microanalysis

  • No preview · Article · Aug 2015 · Microscopy and Microanalysis
  • A. Lobo-da-Cunha · E. Oliveira · Â. Alves · Gonçalo Calado

    No preview · Article · Aug 2015 · Microscopy and Microanalysis

  • No preview · Article · Aug 2015 · Microscopy and Microanalysis

  • No preview · Article · Aug 2015 · Microscopy and Microanalysis
  • A. Lobo-da-Cunha · E. Oliveira · Â. Alves · Gonçalo Calado

    No preview · Article · Aug 2015 · Microscopy and Microanalysis
  • Sílvia C Pinho · Olga C Nunes · Alexandre Lobo-da-Cunha · Manuel F Almeida
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    ABSTRACT: Although alkaline hydrolysis treatment emerges as an alternative disinfection/sterilization method for medical waste, information on its effects on the inactivation of biological indicators is scarce. The effects of alkaline treatment on the resistance of Geobacillus stearothermophilus spores were investigated and the influence of temperature (80 °C, 100 °C and 110 °C) and NaOH concentration was evaluated. In addition, spore inactivation in the presence of animal tissues and discarded medical components, used as surrogate of medical waste, was also assessed. The effectiveness of the alkaline treatment was carried out by determination of survival curves and D-values. No significant differences were seen in D-values obtained at 80 °C and 100 °C for NaOH concentrations of 0.5 M and 0.75 M. The D-values obtained at 110 °C (2.3-0.5 min) were approximately 3 times lower than those at 100 °C (8.8-1.6 min). Independent of the presence of animal tissues and discarded medical components, 6 log10 reduction times varied between 66 and 5 min at 100 °C-0.1 M NaOH and 110 °C-1 M NaOH, respectively. The alkaline treatment may be used in future as a disinfection or sterilization alternative method for contaminated waste. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Jul 2015 · Journal of Environmental Management
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    ABSTRACT: To obtain more data about the digestive system of cephalaspideans, the esophagus and crop of Aglaja tricolorata were investigated using light and electron microscopy. In this cephalaspidean, the low epithelial cells of the anterior esophagus have a border of microvilli covered by a cuticle formed by acid polysaccharides. The esophageal pouches at the hind region of the anterior esophagus contain subepithelial secretory cells filled with electron-dense vesicles rich in neutral polysaccharides and proteins. A ciliated epithelium covers the base of the esophageal pouches. In the crop, the tall columnar epithelium is covered by a cuticle and forms many deep invaginations. The cuticle on the surface of the epithelium contains acid polysaccharides, but the material filling the lumen of the epithelial invaginations consists of neutral polysaccharides and proteins. Epithelial cells of the crop have a border of short microvilli and many mitochondria; lysosome-like bodies and some lipid droplets are present in the apical region. The elongated nucleus, numerous deep cell membrane invaginations and several hemidesmosomes are located at the basal region. Secretory cells are absent in the crop. Numerous large vacuolar cells are present in the connective tissue of the crop. With the pyroantimonate method, calcium was detected in the peripheral vesicles and central vacuole of these cells. WDS X-ray Intensity maps obtained by EPMA (Electron microprobe) confirmed the presence of calcium. This result supports the relationship between the vacuolar cells of aglajids and the calcium cells of pulmonate gastropods. In the posterior esophagus, epithelial cells are similar to the epithelial cells of the crop and secretory cells are also absent.
    Full-text · Article · Nov 2014 · Malacologia
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    ABSTRACT: Four isolates, belonging to the deep-branching phylum Planctomycetes, were recovered from the biofilm of two marine macroalgae, Ulva sp. and Laminaria sp., from the Northern coast of Portugal. These strains were light pink- or red-pigmented; the cells were variable in shape and usually organized in rosettes. They had a dimorphic cell cycle with budding reproduction. The organisms were chemoheterotrophic, strictly aerobic and mesophilic. The 16S rRNA gene sequence analysis showed that the strains belong to the family Planctomycetaceae with Rhodopirellula as the closest genus. The isolates form two separate branches (strain LF1T forms one branch and the strains UC8T, UF3 and UF42 form a second branch) clearly separated from Rhodopirellula baltica with 94.2% and 93.8% 16S rRNA gene sequence similarity, respectively.Based on differential characteristics that distinguish the novel genera from R. baltica, such as cell size and shape, ultrastructure, enzymatic activities, substrate utilization pattern, fatty acid composition, phospholipid profiles and phylogeny we propose that the isolates represent two novel genera of the order Planctomycetales, Roseimaritima ulvae gen. nov., sp. nov. (type strain is UC8T =DSM 25454T = LMG 27778T) and Rubripirellula obstinata gen. nov., sp. nov. (type strain is LF1T = LMG 27779T = CECT 8602T).
    Full-text · Article · Oct 2014 · Systematic and Applied Microbiology
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    ABSTRACT: Twenty two strains of Rhodopirellula were isolated from the epiphytic community of several marine macroalgae and separated into two groups, designated as group B and group C. In this study, we characterized these groups as two novel species belonging to the genus Rhodopirellula. These strains were represented by pleomorphic cells that were arranged in rosettes and formed pink- or red-pigmented colonies. The organisms were chemoorganotrophic and required vitamin B12 for growth. Their optimal temperature for growth was around 25 °C. Major fatty acids were C18:1 ω9c, C16:0 and C16:1 ω7c/C16:1 ω6c. Phosphatidylcholine and phosphatidylglycerol were the major polar lipids. Unidentified phospholipids were also present. The 16S rDNA sequence analysis confirmed the affiliation of these organisms to the order Planctomycetales, genus Rhodopirellula, with R. baltica as the closest phylogenetic relative. The analysis of a partial sequence of the gene encoding the β-subunit of RNA polymerase (rpoB) confirmed the phylogenetic separation of the isolates into two different species of the genus Rhodopirellula. The 16S rRNA sequences from strains of group B revealed their widespread occurrence across the world, whereas strains of group C were not observed before. On the basis of physiological, biochemical, chemotaxonomic and genetic characteristics we propose that our isolates represent two new species of Rhodopirellula, Rhodopirellula rubra sp. nov. (type strain is LF2T = DSM 25,459 = CECT 8075) and Rhodopirellula lusitana sp. nov. (type strain is UC17T = DSM 25,457 = LMG 27,777).
    Full-text · Article · May 2014 · Systematic and Applied Microbiology
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    ABSTRACT: The hemocytes of Octopus vulgaris were morphologically and functionally characterized. Light and electron microscopy (TEM and SEM), and flow cytometry analyses revealed the existence of two hemocyte populations. Large granulocytes showed U-shaped nucleus, a mean of 11.6 μm ± 1.2 in diameter with basophilic granules, polysaccharide and lysosomic deposits in the cytoplasm. Small granulocytes measured a mean of 8.1 μm ± 0.7 in diameter, and have a round nucleus occupying almost the entire cell and few or not granules in the cytoplasm. Flow cytometry analysis showed that large granulocytes are the principal cells that develop phagocytosis of latex beads (rising up to 56%) and ROS after zymosan stimulation. Zymosan induced the highest production of both ROS and NO. This study is the first tread towards understanding the O. vulgaris immune system by applying new tools to provide a most comprehensive morpho-functional study of their hemocytes.
    Full-text · Article · Nov 2013 · Developmental and comparative immunology
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    Olga Maria Lage · Joana Bondoso · Alexandre Lobo-da-Cunha
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    ABSTRACT: Knowledge of the interesting phylum of Planctomycetes has increased in the last decades both due to cultural and molecular methods. Although a restricted number of species have been described to date, this group presents a much larger diversity that has been mainly revealed by molecular ecology studies. Isolation experiments allowed us to get a number of new Planctomycetes taxa that extend the already described ones. In this work we present the ultrastructural morphological characterization of these new taxa as well as we give new details of Aquisphaera giovannonii ultrastructure. Furthermore, our interpretation on Planctomycetes cell envelope is provided.
    Full-text · Article · Jul 2013 · Antonie van Leeuwenhoek
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    Ana Amorim · Elsa Oliveira · Manuel António E. Malaquias · Alexandre Lobo-da-Cunha
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    ABSTRACT: In this study, semi-thin sections stained with histochemical techniques and transmission electron microscopy were used to obtain new data about the morphology and function of the male copulatory apparatus of the cephalaspidean gastropod Bulla striata. The apparatus comprises a vestibule, a penial papilla and a prostate consisting of a coiled unbranched tube ending in a blind caecum. The penial papilla and the coiled tubular prostate are enclosed by a muscular sheath, which is continuous with the muscular tissue of the vestibule. The epithelium lining the lumen of the vestibule is formed by ciliated and mucus-secreting cells. Two new types of subepithelial secretory cells were discovered in this region. The penial papilla is a muscular structure without secretory cells in the epithelium lining the narrow lumen. The tubule that constitutes the prostate possesses a muscular wall and can be divided in three distinct regions: a non-secretory duct connected to the penial papilla, a glandular region rich in large secretory cells and the terminal caecum containing just a few small secretory cells. In the terminal blind caecum, the muscular sheath is fused with the muscular wall of the tubular prostate. Large numbers of spermatozoa were found in the glandular region and in the terminal caecum of the prostate. A new functional mechanism is proposed to explain penial eversion during copulation. This differs from a previous hypothesis in two main aspects: (1) existence of a permanent penial papilla in mature animals acting as a functional penis and (2) functional role of vestibule during copulation, which everts and surrounds the penial papilla, while the latter protrudes outwards.
    Full-text · Article · Jun 2013 · Zoomorphology
  • Catarina Inês Gonçalves · Alexandre Lobo-da-cunha
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    ABSTRACT: This study was conceived to evaluate seasonal changes in the lipid reserves of the digestive gland of the carnivorous intertidal caenogastropod Nucella lapillus, using a stereological approach. Volume density of lipid droplets in the digestive gland, digestive gland weight and volume were assessed in animals collected in March, June, September and December on the Portuguese coast. Gonad development was evaluated to detect any relationship between lipid content in the digestive gland and the reproductive cycle. The quantitative light microscopic analysis demonstrates that lipid droplets are a major component of the digestive gland. In males, the digestive gland and its lipid reserves were quite stable without significant variations throughout the year. In females, the percentage of digestive gland volume occupied by lipid droplets was higher in June and December, coinciding with the highest values of digestive gland volume. Due to the conjugation of these two factors, in June and December the total amount of lipids in the digestive gland was substantially increased in females. In both males and females a relationship between the development status of the gonad and the lipid reserves of the digestive gland was not evident. However, significant differences in the digestive gland lipid reserves were detected between males and females in June and December, pointing to a sex related effect on lipid reserves. To evaluate the use of lipid reserves as energy source in N. lapillus, the consumption of digestive gland lipids was followed during a starvation experiment.
    No preview · Article · May 2013 · Journal of the Marine Biological Association of the UK
  • L Filipe C Castro · Alexandre Lobo-da-Cunha · Maria J Rocha · Ralph Urbatzka · Eduardo Rocha
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    ABSTRACT: A negative correlation between female gonadal maturation kinetics and size variations of hepatic peroxisomes was earlier documented in brown trout, as a probable impact of serum estrogen changes during the reproductive cycle. Herein, we investigated whether the organelle volume/surface dynamics seen in female brown trout liver peroxisomes - without numerical changes within each hepatocyte - is followed by variations in the expression of the membrane peroxisome protein Pex11α gene. For comparison, we also studied males. We find in females a seasonal variation with the highest Pex11α expression in February, which was statistically different from all other tested periods. Overall, the expression of PEX11α had over a fivefold decrease from February to September. This period coincides with the reproductive transition between the earlier post-spawning gonadal remodeling and preparatory staging and the pre-spawning period. Males did not show changes. Our approach allowed the first characterization of a peroxin gene in a teleost, the Pex11α, while offering a correlation scenario were, as we hypothesized, the peroxisomal size kinetics is paralleled by membrane-related gene alterations (measured herein as proxy of Pex11α gene expression). Our data support and expand previous results on the regulation, function and morphology of peroxisome dynamics in brown trout, with a broader interest.
    No preview · Article · Sep 2012 · Comparative biochemistry and physiology. Part A, Molecular & integrative physiology
  • A. D. Resende · A. Lobo-da-Cunha · E. Rocha
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    ABSTRACT: Fish renal morphology has been studied since the 1960’s, but is still incomplete for most species, even for some of the most studied. The functional and morphological diversity and specialization of the fish kidney, due to environmental adaptations, makes this a large subject that remains understudied. References to studies on fish renal structure are given in Table 1. Although authors as Hentschel and Elger contributed to the knowledge of fish renal morphology in a comparative perspective, the knowledge concerning this issue is still reduced. Here we give a short comparative summary of fish renal morphology, using as baseline model the brown trout.
    No preview · Article · Aug 2012 · Microscopy and Microanalysis
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    ABSTRACT: As part of a study of the diversity of planctomycetes, two novel strains, designated OJF2(T) and OJF8, were isolated from the sediments of a freshwater aquarium. The organisms were chemoheterotrophic, spherical and pink-pigmented, had an optimum growth temperature of about 30-35 °C and an optimum pH for growth of around 7.5-8.5. The predominant fatty acids were C(18:1)ω9c and C(16:0). The two strains were able to assimilate several sugars and organic acids. 16S rRNA gene sequence analysis confirmed the affiliation of these organisms to the phylum 'Planctomycetes'; they showed highest similarity to the type strains of Singulisphaera acidiphila (92.4%) and Isosphaera pallida (91.9%). On the basis of physiological, biochemical and chemotaxonomic characteristics, strains OJF2(T) and OJF8 are considered to represent a novel species of a new genus of the order Planctomycetales, for which the name Aquisphaera giovannonii gen. nov., sp. nov. is proposed. The type strain of Aquisphaera giovannonii is OJF2(T) (=CECT 7510(T) =DSM 22561(T)).
    Full-text · Article · Dec 2011 · International Journal of Systematic and Evolutionary Microbiology

Publication Stats

577 Citations
120.46 Total Impact Points

Institutions

  • 1988-2015
    • University of Porto
      • • Department of Microscopy
      • • Instituto de Ciências Biomédicas Abel Salazar (ICBAS)
      Oporto, Porto, Portugal
  • 1994
    • IMAR Marine and Environmental Research Centre
      Coímbra, Coimbra, Portugal