Person:
Domenech Lucas, Miriam

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First Name
Miriam
Last Name
Domenech Lucas
URI
https://hdl.handle.net/20.500.14352/80736
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
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UCM identifierORCIDScopus Author IDWeb of Science ResearcherIDDialnet IDGoogle Scholar ID

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2007 - 20093
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End date: 2009 × Start date: 2007 ×

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Now showing 1 - 3 of 3
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    Ecophysiological characterization of Penicillium expansum population in lleida (Spain)
    (2008) Morales, Hector; Marín, Sonia; Obea, Laura; Domenech Lucas, Miriam; Patiño Álvarez, Aurora Belén; Ramos, Antonio J.; Sanchis, Vicente
    Penicillium expansum, a patulin producer fungus, is the most important fungus causing decay in cold stored both apples and pears. This can lead to patulin contaminated by-products. The aim of this assay was to evaluate the phenotypical and physiological variability in the population of P. expansum that cause fruit spoilage in post-harvest stages in Lleida (Spain). In total, 101 isolates of P. expansum from the 2004 and the 2005 seasons were obtained from decayed fruits. Significant differences were found in the observations from both seasons. Variability of the isolates in each season seemed to be partially explained by differences in growth in media, patulin accumulation and resistance to fungicides. Patulin production was detected in almost 100% of the isolates. Variability existing in P. expansum population could not be totally explained, but the above mentioned variables explained up to 74% of the diversity in some cases. The results obtained point to the existence of different populations of P. expansum in each season and may explain the differences in fungicide resistance observed between both seasons. The capacity to colonize apple flesh and some variables involved in fruit colonization were not a source of variation neither in each season nor when both seasons were compared. As storage rooms are cleaned and disinfected each season, this suggests that each season, the populations in storage rooms develop only from strains capable to colonize apple flesh. This may lead to rapid sporulation and spreading of spores.
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    Versatility of the capsular genes during biofilm formation by Streptococcus pneumoniae
    (Environmental Microbiology, 2009) Domenech Lucas, Miriam; Ernesto García; Miriam Moscoso
    Streptococcus pneumoniae forms part of the natural microbiota of the nasopharynx. For the pneumococcus to cause infection, colonization needs to occur and this process is mediated by adherence of bacteria to the respiratory epithelium. Although the capsular polysaccharide (CPS) of S. pneumoniae is known to be important for infection to occur, its role in colonization is controversial. Biofilm models are starting to emerge as a promising tool to investigate the role of CPS during nasopharyngeal carriage, which is the first step in the dissemination and initiation of a pneumococcal infection. Using a well-defined model system to analyse in vitro biofilm formation in pneumococcus, here we explore the molecular changes underlying the appearance of capsular mutants using type 3 S. pneumoniae cells. Spontaneous colony phase variants show promoter mutations, as well as duplications, deletions and point mutations in the cap3A gene, which codes for a UDP-glucose dehydrogenase (UDP-GlcDH). Increased biofilm-forming capacity could usually be correlated with a reduction both in colony size and in the relative amount of CPS present on the cell surface of each colony variant. However, a mutation in Cap3A Thr83Ile (a strictly conserved residue in bacterial UDP-GlcDHs) that resulted in very low CPS production also led to impaired biofilm formation. We propose that non-encapsulated mutants of pneumococcal type 3 strains are essentially involved in the initial stages (the attachment stage) of biofilm formation during colonization/pathogenesis.
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    Polymerase chain reaction (PCR) identification of Penicillium brevicompactum, a grape contaminant and mycophenolic acid producer
    (Food Additives & Contaminants, 2007) Patiño Álvarez, Aurora Belén; Medina, Á.; Domenech Lucas, Miriam; González Jaén, María Teresa; Jiménez, M.; Vázquez, C.
    Penicillium brevicompactum is a ubiquitous fungal species that contaminates diverse substrates and commodities and produces an array of metabolites toxic to human and animals. The present work has obtained evidence, by liquid chromatography (LC)-ion-trap mass spectrometry, of the ability of P. brevicompactum strains isolated from grapes to produce mycophenolic acid, a potent immunosuppressor. In order to facilitate early diagnosis of this species on commodities for human and animal consumption, a rapid, sensitive and specific polymerase chain reaction (PCR) assay for P. brevicompactum was developed. The specific primers were designed based on the ITS1-5.8S-ITS2ITS (Internal Transcribed Spacers of rRNA genes) multicopy region. This method provides a useful aid to detect the presence of this fungal species in grapes and other commodities in order to prevent the toxins produced entering the food chain.