iBB

Responding to the recent interest of the yeast research community in non-Saccharomyces cerevisiae species of biotechnological relevance, the N.C.Yeastract was associated to YEASTRACT+, a curated repository of known regulatory associations between transcription factors (TFs) and target genes in yeasts. A recent Minireview published in FEMS Yeast Research aims to advertise the update of the existing information since the release of N.C.Yeastract in 2019, and to raise awareness in the community about its potential to help the day-to-day work on non-Saccharomyces species, exploring all the information and bioinformatics tools available in YEASTRACT +. Using simple and widely used examples, a guided exploitation is offered. The usage potentialities of the new CommunityYeastract platform by the yeast community are also discussed. The Minireview is coauthored by a BSRG-iBB team coordinated by Isabel Sá-Correia and including Cláudia P. Godinho, Margarida Palma, Miguel C. Teixeira and the PhD students Miguel Antunes and Marta N. Mota, in collaboration with INESC-ID colleagues.

p28 is a 28 amino acids peptide derived from the bacterial protein azurin. It possesses cell-penetrating capabilities showing preferential enter in cancer cells. Moreover it has been subject in US to two phase I clinical trials as a anticancer agent. In a recent paper published in Journal of Controlled Release, a iBB team (Garizo AR, Dias TP, Fernandes F, Bernardes N, Fialho AM) together with a i3S/UP team (Castro F, Martins C, Almeida A, Barrias CC, Sarmento B) were able for the first time to fabricate p28-functionalized PLGA nanoparticles (NPs) loaded with the EGFR tyrosine kinase inhibitor gefitinib. The results obtained indicate that these NPs interact preferentially with lung cancer cells due to their decoration with p28 peptide. In vitro cytotoxicity assays demonstrate biological activity of the NPs against lung cancer cancer cells. Finally, in vivo studies demonstrated a great potential of the p28-NPs in enhancing the therapeutic effects of gefitinib.

Bacteria associated with coral hosts are diverse and abundant, with recent studies suggesting involvement of these symbionts in host resilience to anthropogenic stress. Combining published and unpublished data, a new article featuring iBB researchers Tina Keller-Costa and Rodrigo Costa among the authors provides a comprehensive overview of the diversity and function of culturable bacteria isolated from tropical, temperate, and cold-water corals. The study, published in the journal mSystems, compiles a total of 3,055 coral-associated isolates described in 52 reports from various laboratories around the world. The work presents a comparative genomic analysis of 74 strains and identifies signatures of potentially beneficial bacterium-coral symbioses among them. Such a resource is an important step in the selection of probiotic candidates, which are being investigated for promoting coral resilience and can potentially be applied in novel reef restoration and rehabilitation efforts. This genome and culture collection is available to the wider research community through the web site http://isolates.reefgenomics.org/ with the hope that many scientists across the globe will ask for access to these resources for future studies.

B. cenocepacia is a contact-dependent bacterium known for its capacity of causing respiratory infections. Among a panel of adhesins used by B. cenocepacia to contact with host cells, trimeric autotransporter adhesins (TAAs) are of particular interest. In a recent paper published in Cellular Microbiology, a BSRG-iBB team (Andreia Pimenta, Nuno Bernardes, Dalila Mil-Homens and Arsénio M Fialho) together with Michelle Kilcoyne and Lokesh Joshi from the National University of Ireland Galway, Galway, Ireland, were able to uncover the roles of the TAA BCAM2418, as an adhesin and the type of host glycans that serve as recognition targets. This work reveals the importance of BCAM2418 as a mediator of early host-bacteria crosstalk.

Octocorals are marine invertebrates abundant in the Portuguese coast, which host complex microbiomes. Yet the functional relationship between host health and its symbiotic consortium has still to be determined. A new study from an international team led by iBB researchers Tina Keller-Costa and Rodrigo Costa employed comparative metagenomics to uncover the functional and phylogenetic features of the microbiomes of healthy tissue from three octocoral species from the Portuguese coast. The authors also explored how the octocoral microbiome shifts to a pathobiome state in one of the coral species. The study reveals that the octocoral microbiome is distinct from those of the environmental surroundings (that is, seawater and sediments), is host genus (but not species) specific, and undergoes complex structural changes in the transition to the dysbiotic state. Host-symbiont recognition, abiotic-stress response, micronutrient acquisition, and an antiviral defence arsenal comprising multiple restriction endonucleases, CRISPR/Cas systems, and phage lysogenization regulators are signatures of prokaryotic communities in octocorals. The authors argue that these features collectively contribute to the stabilization of host-microbe symbiosis in octocorals and constitute beneficial traits that can guide future studies on coral reef conservation and microbiome therapy. The article was published in the journal Microbiome.

Burkholderia cenocepacia is a human contact-dependent pathogenic bacterium known for its capacity of causing severe opportunistic respiratory infections. B. cenocepacia uses a complex machinery for primary adherence with host cells. In a recent paper published in Scientific Reports, a BSRG-iBB team (Andreia Pimenta, Nuno Bernardes, Dalila Mil-Homens and Arsénio M Fialho) together with Marta M Alves from CQE, IST, have developed a RNASeq-based approach that led to identify adhesion candidate genes that were not previously reported in the context of a B. cenocepacia infection. This study presents a innovative technique in which their use Giant Plasma Membrane Vesicles (GPMVs) from a bronchial epithelial cell line as a cell-like alternative to investigate the steps involved in the adhesion process of B. cenocepacia.

Little is known about the structure and diversity of chitin-degrading microbial communities across marine niches. Researchers from BSRG-iBB, including PhD student Rúben Silva and former students Inês Raimundo (now a PhD student at KAUST) and Laurence Meunier (now a PhD student at University of Brussels), and led by Rodrigo Costa and Tina Keller-Costa have shed light on chitin processing within the microbiomes of marine sponges, octocorals, sediments, and seawater. The study, published in Microbiome, integrates cultivation-dependent and -independent approaches to unveil chitin degradation pathways across diverse marine bacteria. Functional metagenomics revealed that the marine sponge microbiome is rich in polysaccharide deacetylases, suggesting the ability of this consortium to convert chitin into its more biotechnologically versatile form - chitosan. The findings further suggest that chitin is processed via multiple mechanisms across marine micro-niches, favoring the hypothesis that inter-species microbial cross-feeding facilitates the co-existence of chitin users within the microbiomes of filter-feeding marine invertebrates. The study also reports on new chitinolytic enzymes from the genus Aquimarina that may find use in the blue biotechnology sector.

The attachment of bacteria and other microbes to natural and artificial surfaces leads to the development of biofilms, which can further cause nosocomial infections. Thus, an important field of research is the development of new materials capable of preventing the initial adhesion of pathogenic microorganisms. In this work, novel polymer/particle composite materials were developed and characterized with respect to their mechanical, chemical and surface properties. Both S. aureus and C. glabrata exhibit a reduced capacity to adhere to the newly developed nanomaterials used in this study, thus showing their potential for bio-medical applications. This study, led by researchers from LAAS-CNRS, Toulouse, and co-authored by Mafalda Cavalheiro and Miguel Cacho Teixeira from BSRG-iBB, was just published in Nanomaterials.

It is now known that a significant fraction of the total microbial diversity in nature exists at low abundance, which has given rise to an increasing number of studies on the so-called rare biosphere. With the fast-paced improvement of novel molecular technologies, surveys on the dynamics of the rare biosphere across the three domains of life (Bacteria, Archaea, Eukarya) and several environments are now possible. Importantly, this research field is transitioning from a taxonomy-driven to a functionally driven analysis, whereby the roles of rare microorganisms in boosting ecosystem functioning are addressed. In this context, a team formed by Prof. Rodrigo Costa (iBB-BSRG), Prof. Catarina Magalhães (CIIMAR-ECOBIOTEC), and PhD candidate Francisco Pascoal (Porto University), delineate the state of the art in our current knowledge of the microbial Rare Biosphere, highlighting the role of viruses in the regulation of low abundance microbial populations. The review article, published in FEMS Microbiology Ecology, also examines current concepts and methods employed in the study of the rare biosphere, integrating emerging knowledge of low abundance microorganisms into a larger ecological theory framework.

Saccharomyces boulardii has been widely used, for more than 50 years, as a human probiotic. Nonetheless, the molecular basis underlying its mode of action is scarcely understood. In this study, global gene expression analysis, resorting to Illumina- based RNA-sequencing, was conducted to analyze differential gene expression patterns in S. cerevisiae and S. cerevisiae var. boulardii in GI- tract like medium. Additionally, based on the construction of an S. cerevisiae var. boulardii database, a global comparison between gene promoter sequences in S. cerevisiae and S. cerevisiae var. boulardii strains was conducted. The obtained results shed light into the molecular basis of the differential probiotic phenotypes displayed by these two closely related yeasts. The knowledge gathered through this study, by a team led by Miguel Cacho Teixeira, BSRG-iBB, and Pedro T Monteiro, INESC-ID, and just published in Genomics, is expected to contribute to guide the design of more rationale, probiotic-based, therapeutic approaches.

PI(4,5)P2 is a phospholipid found mostly in the plasma membrane of eukaryotic cells, where it plays a crucial role in processes like vesicle trafficking, cytoskeletal regulation, ion channel function, viral assembly and budding. While most phospholipids show considerable acyl-chain diversity, PI(4,5)P2 lipids are exceptionally enriched in specific acyl-chains, the most frequent composition in mammalian cells being 1-stearoyl-2-arachidonyl (18:0 20:4). The biological functions that call for this specific enrichment are still not fully clear. In a recent paper published in Communications Chemistry, a BSIRG-iBB team led by Fábio Fernandes together with the teams of Dr. Nuno Santos (IMM) and Dr. Manuel Melo (ITQB) identified a previously unreported increase in membrane order upon calcium-dependent PI(4,5)P2 clustering. Remarkably, the interaction of saturated PI(4,5)P2 with calcium culminated in the formation of gel nanodomains for fully saturated PI(4,5)P2, and the formation of these gel domains was abrogated in the presence of 18:0 20:4 polyunsaturated PI(4,5)P2. These results support a role of (18:0 20:4)PI(4,5)P2 in inhibiting the formation of highly ordered PI(4,5)P2 nanodomains in the plasma membrane.

The role of the cell wall in yeast response and tolerance to stress is frequently neglected. A BSRG-iBB research paper just published in Scientific Reports, provides, for the first time, a comprehensive view of the alterations occurring at the cell wall in a yeast population adapting to sub-lethal stress induced by acetic acid. The results reveal changes to the cell wall polysaccharide composition and nanomechanical properties, as well as alterations in the transcript levels of key cell wall biosynthetic genes. This paper reinforces the notion that the adaptive yeast response to acetic acid involves coordinated alterations of the cell wall at the biophysical and molecular levels. The gathered knowledge is important for the design of superior industrial strains and for the efficient control of the deleterious activity of spoilage yeasts, particularly in the Food Industry. This research work is first-authored by the PhD student of the PhD programme in Biotechnology and Biosciences Ricardo Ribeiro (FCT_DP AEM fellowship), performed under the supervision of Isabel Sá-Correia. This collaborative study with Fábio Fernandes (BSIRG-iBB) and Mário S. Rodrigues and his team (BioISI, Faculty of Sciences, ULisboa), is also coauthored by Cláudia Godinho (posdoc researcher) and the PhD student Nuno Bourbon-Melo (FCT_DP BIOTECnico) from the BSRG-iBB team.

Agro-industrial residues rich in pectin are generated in high amounts worldwide from the sugar industry or the industrial processing of fruits and vegetables. A recent paper by BSRG-iBB researchers, published in the Journal of Fungi (special issue “Yeast Biorefineries” (edited by Isabel Sá-Correia and Naseem Gaur), describes the optimization of the performance of Rhodotorula strains envisaging the use of the major carbon sources present in Sugar Beet Pulp (SBP) hydrolysates. SBP valorization through the production of lipids and carotenoids by the oleaginous red yeasts examined, supported by complete catabolism of the major carbon sources present, looks promising for industrial implementation. The work was conducted by the PhD student of the IST PhD Programme in Biotechnology and Biosciences Luís C. Martins (FCT_DP AEM programme fellowship) under the supervision of Isabel Sá-Correia. This work was developed in the context of the ERA-NET-Industrial Biotechnology-2 project, “YEASTPEC-Engineering of the yeast Saccharomyces cerevisiae for bioconversion of pectin-containing agro-industrial side-streams”.

Cellular components that contribute to both pathogenesis and drug resistance are among the most promising drug targets in human pathogens. In this study, the uncharacterized drug:H+ antiporter CgTpo4 was shown to play a role in Candida glabrata virulence in the infection model G. mellonella. The underlying mechanism was demonstrated to include a role in AntiMicrobial Peptide (AMP) resistance, compatible with the observed immune response deployed by G. mellonella upon C. glabrata infection. These results, emerging from a collaboration between BSRG members, led by Miguel Cacho Teixeira and including Arsénio Fialho and Dalila Mil-Homens, were just published in International Journal of Molecular Sciences and are expected to contribute to design more suitable antifungal therapeutic strategies.

Methanol is a promising feedstock for metabolically competent yeast strains-based biorefineries. However, methanol toxicity can limit the productivity of these bioprocesses. For this reason, the identification of genes whose expression is required for maximum methanol tolerance is important for mechanistic insights and rational genomic manipulation to obtain more robust methylotrophic yeast strains. The chemogenomic analysis performed in this new BSRG-iBB study provided new valuable information on genes and potential regulatory networks involved in overcoming methanol toxicity in the model yeast Saccharomyces cerevisiae. The article was just published in the Journal of Fungi and belongs to the Special Issue “Yeast Biorefineries” (edited by Isabel Sá-Correia and Naseem A. Gaur). The article has as co-authors the PhD students of the IST Biotechnology and Biosciences PhD Programme ( FCT_DP Applied and Environmental Microbiology) Marta N. Mota (first  author) and Luís C. Martins, under Prof. Isabel Sá-Correia’s supervision. The gathered knowledge is an important starting point for the improvement of methanol tolerance in yeasts capable of catabolizing and copying with methanol concentrations present in promising bioeconomy feedstocks, including industrial residues.