Elena Rivas Marin

Universidad Pablo de Olavide | UPO · Centro Andaluz de Biología del Desarrollo

Carotenoids are isoprenoid lipids found across the tree of life with important implications in oxidative stress adaptations, photosynthetic metabolisms, as well as in membrane dynamics. The canonical view is that C40 carotenoids are synthesized from phytoene and C30 carotenoids from diapophytoene. Squalene is mostly associated with the biosynthesis...

Squalene is mostly associated with the biosynthesis of polycyclic triterpenes. Although there have been suggestions that squalene could be involved in the biosynthesis of carotenoids, functionally and evolutionarily related to polycyclic triterpenes, evidence of this 'squalene route' in nature was lacking. We demonstrate that planctomycetes synthes...

Access to axenic cultures is crucial to extend the knowledge of the biology, lifestyle or metabolic capabilities of bacteria from different phyla. The phylum Planctomycetes is an excellent example since its members display an unusual cell biology and complex lifestyles. As a contribution to the current collection of axenic planctomycete cultures, h...

Planctomycetes are ubiquitous bacteria with environmental and biotechnological relevance. Axenic cultures of planctomycetal strains are the basis to analyse their unusual biology and largely uncharacterised metabolism in more detail. Here, we describe strain Mal4T isolated from marine sediments close to Palma de Mallorca, Spain. Strain Mal4T displa...

Under ever-changing environmental conditions, the General Stress Response (GSR) represents a lifesaver for bacteria in order to withstand hostile situations. In α-proteobacteria, the EcfG-type extracytoplasmic function (ECF) σ factors are the key activators of this response at the transcriptional level. In this work, we address the hierarchical fun...

Polycyclic triterpenes are members of the terpene family produced by the cyclisation of squalene. The most representative polycyclic triterpenes are hopanoids and sterols, the former are mostly found in bacteria while sterols are largely limited to eukaryotes, albeit with a growing number of bacterial exceptions. Given their important role and omni...

Most bacteria divide by binary fission using an FtsZ-based mechanism that relies on a multi-protein complex, the divisome. In the majority of non-spherical bacteria another multi-protein complex, the elongasome, is also required for the maintenance of cell shape. Components of these multi-protein assemblies are conserved and essential in most bacte...

When it comes to the discovery and analysis of yet uncharted bacterial traits, pure cultures are essential as only these allow detailed morphological and physiological characterization as well as genetic manipulation. However, microbiologists are struggling to isolate and maintain the majority of bacterial strains, as mimicking their native environ...

Sterols and hopanoids are chemically and structurally related lipids mostly found in eukar-yotic and bacterial cell membranes. Few bacterial species have been reported to produce sterols and this anomaly had originally been ascribed to lateral gene transfer (LGT) from eukaryotes. In addition, the functions of sterols in these bacteria are unknown a...

These are exciting times for PVC researchers! The PVC superphylum is composed of the bacterial phyla Planctomycetes, Verrucomicrobia, Chlamydiae (those three founders giving it its name), Lentisphaerae and Kirimatiellaeota as well as some uncultured candidate phyla, such as the Candidatus Omnitrophica (previously known as OP3). Despite early debate...

Bacteria from the Planctomycetes, Verrucomicrobia, and Chlamydiae (PVC) superphylum are exceptions to the otherwise dominant mode of division by binary fission, which is based on the interaction between the FtsZ protein and the peptidoglycan (PG) biosynthesis machinery. Some PVC bacteria are deprived of the FtsZ protein and were also thought to lac...

Division and cell wall cluster and PG synthesis protein detection in PVC. Due to the divergence of the PVC species from model organisms and for the sake of completeness, two complementary searches were combined (Sheet 1). We first performed two iterations of Psi-Blast using the W. chondrophila (Sheet 2) and E. coli (Sheet 3) proteins as a query on...

Bacteria belonging to the Planctomycetes, Verrucomicrobia, Chlamydiae (PVC) superphylum are of interest for biotechnology, evolutionary cell biology, ecology and human health. Some PVC species lack a number of typical bacterial features while others possess characteristics that are usually more associated to eukaryotes or archaea. For example, the...

Regulation of tetralin biodegradation operons is one of the examples of unconventional LysR-type mediated transcriptional regulation. ThnR activates transcription from two divergent and closely located promoters PB and PC. Although ThnR activates each promoter independently, transcription from each one increases when both promoters are together. Mu...

Previous genetic studies in Sphingomonas macrogolitabida strain TFA have established that expression of genes involved in tetralin biodegradation (thn genes) requires the function of the LysR type activator ThnR and also ThnY. Sequence comparison indicated that ThnY is homologous to bacterial oxygenase-coupled NAD(P)H-dependent ferredoxin reductase...

The genes required for tetralin biodegradation by Sphingomonas macrogolitabida strain TFA are clustered in two divergent and closely linked operons. ThnR, a LysR-type regulator, activates transcription from each operon in response to tetralin. The regulatory thnR gene is co-transcribed with the catabolic genes thnC, thnA3 and thnA4, resulting in po...