Institute Tecnologia Quimica e Biologica ITQB UNL

Oeiras, Portugal

Institute Tecnologia Quimica e Biologica ITQB UNL

Oeiras, Portugal
SEARCH FILTERS
Time filter
Source Type

Visagie C.M.,Stellenbosch University | Visagie C.M.,Fungal Biodiversity Center | Visagie C.M.,Eastern Cereal and Oilseed Research Center | Houbraken J.,Fungal Biodiversity Center | And 7 more authors.
Persoonia: Molecular Phylogeny and Evolution of Fungi | Year: 2013

Current literature accepts 17 species in Penicillium section Sclerotiora. Several produce colonies in bright yellow to orange colours and have monoverticillate conidiophores, apart from P. herquei, P. malachiteum and P. nodo-sitatum, which are biverticillate. The focus of this paper is to refine the concepts of the species currently accepted in the section and introduce five new species, named after the Dutch Royal family as P. vanoranjei, P. maximae, P. amaliae, P. alexiae and P. arianeae. Penicillium vanoranjei produces orange (Dutch = oranje) colonies in culture, and is named after Willem-Alexander Claus George Ferdinand, 'Zijne Koninklijke Hoogheid de Prins van Oranje' (translated from Dutch as: 'His Royal Highness the Prince of Orange') and his family, to coincide with his coronation. We review the current taxonomic positions of P. lilacinoechinulatum and P. nodositatum, both currently considered to be synonyms of P. bilaiae. Sequence data generated in this study show that both species are phylogenetically distinct. Penicillium lilacinoechinulatum is closely related to P. amaliae sp. nov., whereas P. nodositatum does not belong to Penicillium sensu stricto. All species were compared morphologically and phylogenetically, based on β-tubulin and calmodulin DNA data. A table summarising the morphological characters of all species is included, together with photomicrographs and recommended DNA markers for identification. © 2013 Naturalis Biodiversity Center & Centraalbureau voor Schimmelcultures.


PubMed | University of Ottawa, Instituto Of Tecnologia Quimica E Biologica Itqb Unl, Stellenbosch University, Eastern Cereal and Oilseed Research Center and 2 more.
Type: | Journal: Persoonia | Year: 2014

Current literature accepts 17 species in Penicillium section Sclerotiora. Several produce colonies in bright yellow to orange colours and have monoverticillate conidiophores, apart from P. herquei, P. malachiteum and P. nodositatum, which are biverticillate. The focus of this paper is to refine the concepts of the species currently accepted in the section and introduce five new species, named after the Dutch Royal family as P. vanoranjei, P. maximae, P. amaliae, P. alexiae and P. arianeae. Penicillium vanoranjei produces orange (Dutch = oranje) colonies in culture, and is named after Willem-Alexander Claus George Ferdinand, Zijne Koninklijke Hoogheid de Prins van Oranje (translated from Dutch as: His Royal Highness the Prince of Orange) and his family, to coincide with his coronation. We review the current taxonomic positions of P. lilacinoechinulatum and P. nodositatum, both currently considered to be synonyms of P. bilaiae. Sequence data generated in this study show that both species are phylogenetically distinct. Penicillium lilacinoechinulatum is closely related to P. amaliae sp. nov., whereas P. nodositatum does not belong to Penicillium sensu stricto. All species were compared morphologically and phylogenetically, based on -tubulin and calmodulin DNA data. A table summarising the morphological characters of all species is included, together with photomicrographs and recommended DNA markers for identification.


Groves P.,Institute Tecnologia Quimica e Biologica ITQB UNL | Groves P.,CSIC - Biological Research Center | Strzelecka-Kiliszek A.,Nencki Institute of Experimental Biology | Sekrecka-Belniak A.,Nencki Institute of Experimental Biology | And 6 more authors.
Organic and Biomolecular Chemistry | Year: 2013

Fluorescent analogues provide important tools for biochemical/biophysical research. However, the analogues contain chemical modifications much larger than those known to affect ligand-binding, such as the inversion of a carbon centre or substitution of an atom. We lack experimental tools and protocols to select the most appropriate fluorescent analogue. Herein, we use several NMR spectroscopy methods, including Saturation Transfer Difference (STD), STD competition and transferred nuclear Overhauser effect spectroscopy (Tr-NOESY), as tools to select appropriate fluorescent probes. Annexin A6 (AnxA6) is a ubiquitous protein that forms in vitro GTP-induced ion channels. We used this protein as a model and screened guanosine triphosphate (GTP) and four fluorescent analogues against AnxA6. STD reported that the GTP moiety of all ligands made similar contacts with the protein, despite additional interactions between the fluorescent tags and AnxA6. Competition STD experiments verified that the analogues and GTP bind to the same site. Tr-NOESY indicated that the bound conformation of the base relative to ribose is altered for some analogues compared to GTP. MANT-GTP or the BODIPY thioester of guanosine 5′-O-(3-thiotriphosphate) are the most suitable fluorescent analogues for AnxA6, according to NMR. These results reveal NMR as a useful technique to select and design proper fluorescent tags for biochemical/biophysical assays.© 2013 The Royal Society of Chemistry.


Mendes M.D.,University of Lisbon | Barroso J.G.,University of Lisbon | Oliveira M.M.,Institute Tecnologia Quimica e Biologica ITQB UNL | Trindade H.,University of Lisbon
Journal of Plant Physiology | Year: 2014

Thymus caespititius Brot. is an Iberian endemic species, whose essential oils possess high polymorphism. They consist mostly of mono- and sesquiterpene, some of them with interest for the pharmaceutical and food industries. The search for terpene synthase genes was performed in three in vitro T. caespititius genotypes. For these plants, the expression of a previously described γ-terpinene synthase gene, Tctps2, was confirmed, occurring concomitantly with a new gene encoding an enzyme with similar activity, named Thymus caespititius terpene synthase 4 (Tctps4). The two isogenes were isolated and functionally characterized in the three plant genotypes. Alignment of the two Tctps revealed a transit peptide much shorter in Tctps4 than in Tctps2 (3-4 amino acids instead of 47). The Tctps4 open reading frame is shorter than Tctps2 (1665 bp versus 1794 bp). The amino acid sequence of both γ-terpinene synthases shared an 88% pairwise identity. The fact that T. caespititius carries two isogenes for γ-terpinene synthases, suggests gene duplication along the evolutionary process, followed by mutations leading to the differentiation of both genes. These mutations didn't compromise protein activity. A high accumulation of transcripts from both genes was found in shoots of in vitro plantlets, while in roots they could not be detected. Still, γ-terpinene levels in aerial parts were reduced, probably due to fast conversion into carvacrol and thymol, the main components from T. caespititius essential oils. This study is a contribution to the identification of terpene synthase genes in Lamiaceae. © 2014 Elsevier GmbH.


Mendes M.D.,University of Lisbon | Figueiredo A.C.,University of Lisbon | Margarida Oliveira M.,Institute Tecnologia Quimica e Biologica ITQB UNL | Trindade H.,University of Lisbon
Plant Cell, Tissue and Organ Culture | Year: 2013

Thymus caespititius Brot. is an important aromatic species, due to synthesis and production of essential oils for the pharmaceutical and food industries. In the present study, levels of essential oils from two chemotypes, including carvacrol/thymol (CT) and sabinene/carvacrol (SC), were evaluated in proliferating shoot cultures (6-12 subcultures following establishment) and compared to those from field-grown plants. The essential oils were isolated by hydrodistillation and analysed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Cultures grown under in vitro culture conditions, evaluated over six subcultures, were found to maintain stable composition of essential oils. For the CT chemotype, carvacrol (42 %) and thymol (23 %) were the main essential oil components detected in field-grown plants; in proliferating shoot cultures the levels detected attained 17-25 % in the case of carvacrol and 18-23 % in that of thymol, closely followed by carvacryl acetate (15-23 %) and thymyl acetate (11-15 %). For the SC chemotype, carvacrol (13-28 %), sabinene (18-45 %), and thymol (9-12 %) were the main essential oil components detected in both field-grown and proliferating shoot cultures. Our experiments showed that the essential oil composition in proliferating shoot cultures was not only stable, but also qualitatively similar to that of field-grown plants, notwithstanding minor quantitative differences. © 2012 Springer Science+Business Media Dordrecht.


PubMed | University of Lisbon and Institute Tecnologia Quimica e Biologica ITQB UNL
Type: Journal Article | Journal: Journal of plant physiology | Year: 2014

Thymus caespititius Brot. is an Iberian endemic species, whose essential oils possess high polymorphism. They consist mostly of mono- and sesquiterpene, some of them with interest for the pharmaceutical and food industries. The search for terpene synthase genes was performed in three in vitro T. caespititius genotypes. For these plants, the expression of a previously described -terpinene synthase gene, Tctps2, was confirmed, occurring concomitantly with a new gene encoding an enzyme with similar activity, named Thymus caespititius terpene synthase 4 (Tctps4). The two isogenes were isolated and functionally characterized in the three plant genotypes. Alignment of the two Tctps revealed a transit peptide much shorter in Tctps4 than in Tctps2 (3-4 amino acids instead of 47). The Tctps4 open reading frame is shorter than Tctps2 (1665 bp versus 1794 bp). The amino acid sequence of both -terpinene synthases shared an 88% pairwise identity. The fact that T. caespititius carries two isogenes for -terpinene synthases, suggests gene duplication along the evolutionary process, followed by mutations leading to the differentiation of both genes. These mutations didnt compromise protein activity. A high accumulation of transcripts from both genes was found in shoots of in vitro plantlets, while in roots they could not be detected. Still, -terpinene levels in aerial parts were reduced, probably due to fast conversion into carvacrol and thymol, the main components from T. caespititius essential oils. This study is a contribution to the identification of terpene synthase genes in Lamiaceae.


Komiazyk M.,Institute Tecnologia Quimica e Biologica ITQB UNL | Komiazyk M.,Nencki Institute of Experimental Biology | Palczewska M.,Institute Tecnologia Quimica e Biologica ITQB UNL | Sitkiewicz I.,Polish National Medicines Institute | Groves P.,Institute Tecnologia Quimica e Biologica ITQB UNL
Polish Journal of Microbiology | Year: 2014

Plants contain a broad spectrum of small molecules with potential antimicrobial properties. Here, we review the antimicrobial activities of plant extracts against enterotoxic bacteria encoding AB5 toxins, including Vibrio cholerae, Shigella dysenteriae and enterotoxic Escherichia coli strains. Several plant extracts have strong antimicrobial effects and the potential to boost Oral Rehydration Therapy, which is the first line of treatment for acute diarrhea.


Ma P.,University of Leeds | Ma P.,Institute Tecnologia Quimica e Biologica ITQB UNL | Nishiguchi K.,Kyushu University | Yuille H.M.,University of Leeds | And 3 more authors.
FEBS Letters | Year: 2011

Siamycin I disrupts growth and quorum sensing in Enterococcus faecalis. Using purified intact protein, we demonstrate here that quorum membrane sensor kinase FsrC is a direct target of siamycin I, reducing pheromone-stimulated autophosphorylation activity by up to 91%. Inhibition was non-competitive with ATP as substrate. Other ATP-binding enzymes were also inhibited, including nine other membrane sensor kinases of E. faecalis, Rhodobacter sphaeroides PrrB, porcine Na+-dependent ATPase and the catalytic subunit of bovine protein kinase A, but not bacterial β-galactosidase, confirming targeted inhibition of a wide range of ATP dependent reactions, and elucidating a likely mechanism underlying the lethality of the inhibitor. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.


Balogh J.,University of Coimbra | Balogh J.,Lund University | Balogh J.,Institute Tecnologia Quimica e Biologica ITQB UNL
Advances in Colloid and Interface Science | Year: 2010

Microemulsions based on nonionic surfactants of the ethylene oxide alkyl ether type CmEn, have been studied thoroughly for around 30 years. Thanks to the considerable amount of published data available on these systems, it is possible to observe trends to make predictions of phase diagrams not yet determined. Strey and Kahlweit, and subsequently Sottmann and Strey, with coworkers have studied and published phase diagrams for systems with a fixed ratio of oil to water, varying the surfactant, the so-called Kahlweit fish-cut diagrams. Some properties of the phase diagrams can be scaled to become general and not system dependent. Here are shown two examples of scaling data from phase diagrams and the use of trends to determine phase diagrams, both inside and outside a dataset. The trends of microemulsions with fixed ratio of surfactant to oil, the so-called Lund-cut diagrams, are also investigated. The trends are used to determine a new phase diagram and this is compared with previously unpublished experimental data on C12E5- Octadecane-Water system. The scalings and trends make it possible to get good estimations of many of the important properties of the phase diagrams, both temperatures and surfactant concentrations of interest, by investigating one sample in the 3-phase region of the balanced fish-cut diagram. © 2010 Elsevier B.V. All rights reserved.


PubMed | Institute Tecnologia Quimica e Biologica ITQB UNL
Type: Journal Article | Journal: Organic & biomolecular chemistry | Year: 2013

Fluorescent analogues provide important tools for biochemical/biophysical research. However, the analogues contain chemical modifications much larger than those known to affect ligand-binding, such as the inversion of a carbon centre or substitution of an atom. We lack experimental tools and protocols to select the most appropriate fluorescent analogue. Herein, we use several NMR spectroscopy methods, including Saturation Transfer Difference (STD), STD competition and transferred nuclear Overhauser effect spectroscopy (Tr-NOESY), as tools to select appropriate fluorescent probes. Annexin A6 (AnxA6) is a ubiquitous protein that forms in vitro GTP-induced ion channels. We used this protein as a model and screened guanosine triphosphate (GTP) and four fluorescent analogues against AnxA6. STD reported that the GTP moiety of all ligands made similar contacts with the protein, despite additional interactions between the fluorescent tags and AnxA6. Competition STD experiments verified that the analogues and GTP bind to the same site. Tr-NOESY indicated that the bound conformation of the base relative to ribose is altered for some analogues compared to GTP. MANT-GTP or the BODIPY thioester of guanosine 5-O-(3-thiotriphosphate) are the most suitable fluorescent analogues for AnxA6, according to NMR. These results reveal NMR as a useful technique to select and design proper fluorescent tags for biochemical/biophysical assays.

Loading Institute Tecnologia Quimica e Biologica ITQB UNL collaborators
Loading Institute Tecnologia Quimica e Biologica ITQB UNL collaborators