Biology subjects

Liebana, R.

Publications and source records attributed to Liebana, R..

4 recordsLinked to original sources

bioRxiv2024

Community successional patterns and inter-kingdom interactions during granular biofilm development

Aerobic granular sludge is a compact and efficient biofilm process used for wastewater treatment which has received much attention and is currently being implemented worldwide. The microbial associations and their ecological implications occurring during granule development, especially those involving inter-kingdom interactions, are poorly understood. In this work, we monitored the prokaryote and eukaryote community composition and structure during the granulation of activated sludge for 343 days in a sequencing batch reactor (SBR), and investigated the influence of abiotic and biotic factors on the granule development. Sludge granulation was accomplished with low-wash out dynamics at long settling times, allowing for the microbial communities to adapt to the SBR environmental conditions. The sludge granulation and associated changes in microbial community structure could be divided into three stages: floccular, intermediate, and granular. The eukaryotic and prokaryotic communities showed parallel successional dynamics, with three main sub-communities identified for each kingdom, dominating in each stage of sludge granulation. Although inter-kingdom interactions were shown to affect community succession during the whole experiment, during granule development random factors like the availability of settlement sites or drift acquired increasing importance. The prokaryotic community was more affected by deterministic factors, including reactor conditions, while the eukaryotic community was to a larger extent shaped by biotic interactions (including inter-kingdom interactions) and stochasticity.

microbiology↗

bioRxiv2023

Diversity and biotechnological potential of filamentous fungi isolated from sediments of Basque estuaries

Marine environments harbor a vast diversity of microorganisms, which have developed multiple strategies to adapt to challenging conditions and represent a valuable source for new products such as pigments, enzymes and bioactive compounds. From all microorganisms inhabiting marine environments, fungi have been the least studied, despite their ubiquitous presence and great biotechnological potential. Here, we focused on the isolation and characterization of filamentous fungi from marine sediment samples, which were collected along the Basque coast in Spain. Through phenotypic characterization, we identified isolates potentially able to produce secondary metabolites or grow on minimal culture medium supplemented with recalcitrant algal polysaccharides. Based on this screening, two Sordariomycetes isolates were selected for further analyses through genome sequencing and omics techniques: 1) a Marquandomyces marquandii strain able to stain the culture medium in yellow, indicative of secretion of pigments and secondary metabolites and 2) an Albophoma yamanashiensis strain able to grow in minimal culture medium supplemented with the recalcitrant algal polysaccharide fucoidan. Fungal co-culture experiments suggested an inhibitory effect of the secretome of M. marquandii on fungal growth. Under culture conditions inducing pigment secretion, a set of secondary metabolite gene clusters were differentially expressed, as analysed by RNA-seq. On the other hand, transcriptomic and proteomic experiments on A. yamanashiensis unveiled the enzymatic activities expressed in response to the presence of fucoidan. Overall, our results indicate that the isolated marine fungal strains could serve as a source of new enzymatic activities and secondary metabolites.

microbiology↗

bioRxiv2020

Diacylglycerol kinase ζ deficiency triggers early signs of aplastic anemia in mice

Acquired aplastic anemia (AA) is a rare blood disorder that results from immune-mediated destruction of bone marrow (BM) progenitor cells. Improved understanding of the mechanisms that favor T cell attack in BM could help to improve early diagnosis and disease treatment. Diacylglycerol kinase {zeta} (DGK{zeta}) limits T cell responses through phosphorylation of diacylglycerol into phosphatidic acid. This reaction attenuates diacylglycerol-dependent activation of the Ras/ERK/CD69 and PKC{theta}/NF{kappa}B pathways in response to antigen. Here we show that, in contrast to the lack of basal activation observed in peripheral lymphoid organs, DGK{zeta}-/- mice showed increased numbers of activated T cells in BM, together with a significant increase in IFN{gamma} as well as perforin and granzyme B and C levels. The enhanced presence of T cells in DGK{zeta}-/- mouse BM correlates with reduced BM cellularity, impaired hematopoiesis, and lower frequency of circulating red cells, granulocytes, and platelets. Our studies coincide with the recent characterization of lower DGK{zeta} expression in T cells isolated from the BM of patients with acquired AA, and suggest that limited DGK{zeta} expression and/or functions predispose to T cell-mediated BM destruction. This study identifies the BM as a niche particularly sensitive to DGK{zeta} deficiency and indicates that this mouse model could be of interest for studying the mechanism that contributes to AA development. Key pointsO_LIDGK{zeta}-deficiency in mice results in larger numbers of CD69-positive T cells in bone marrow, with enhanced expression of IFN{gamma} and lytic enzymes. C_LIO_LIDGK{zeta} loss recapitulates many clinical aspects of human aplastic anemia, identifying a critical hub for immune system-dependent bone marrow failure. C_LI Visual abstract O_FIG O_LINKSMALLFIG WIDTH=140 HEIGHT=200 SRC="FIGDIR/small/136390v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@d485b2org.highwire.dtl.DTLVardef@9599c1org.highwire.dtl.DTLVardef@1a17842org.highwire.dtl.DTLVardef@1de640d_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2018

Deterministic and stochastic processes influence the reproducibility of microbial community assembly during aerobic granulation

Aerobic granular sludge is an energy efficient and compact biofilm process for wastewater treatment which has received much attention during the last decades and is now being implemented in full-scale. However, the factors involved in microbial community assembly during formation of granules are poorly understood and little is known about the reproducibility in treatment performance and community structure. Here we show that both deterministic and stochastic factors exert a dynamic influence during microbial community assembly into granular sludge. During granulation, the microbial communities in three replicate sequencing batch reactors followed similar successional trajectories of the most abundant taxa and showed similar dynamics in diversity. Deterministic factors dominated the assembly of the most abundant community members as the microbial community transitioned from floccular to granular form. Stochastic factors mostly affected rare members of the communities and caused the microbial community structure to diverge in one of the reactors; however, this did not have an impact on the treatment performance. This demonstrates that the reactor function and the dynamics of the most abundant community members are in fact reproducible during the formation of aerobic granules.

microbiology↗