Biology subjects

Tejedor-Sanz, S.

Publications and source records attributed to Tejedor-Sanz, S..

4 recordsLinked to original sources

bioRxiv2024

Functional plasticity of HCO3- uptake and CO2 fixation in Cupriavidus necator H16

Uptake and fixation of CO2 are central to strategies for CO2-based biomanufacturing. Cupriavidus necator H16 has emerged as a promising industrial host for this purpose. Despite its prominence, the ability to engineer C. necator inorganic carbon uptake and fixation is underexplored. Here, we test the role of endogenous and heterologous genes on C. necator inorganic carbon metabolism. Deletion of one of the four carbonic anhydrases in C. necator, {beta}-carbonic anhydrase can, had the most deleterious effect on C. necator autotrophic growth. Replacement of this native uptake system with several classes of dissolved inorganic carbon (DIC) transporters from Cyanobacteria and chemolithoautotrophic bacteria recovered autotrophic growth and supported higher cell densities compared to wild-type (WT) C. necator in saturating CO2 in batch culture. Several heterologous strains with Halothiobacillus neopolitanus DAB2 (hnDAB2) expressed from the chromosome in combination with diverse rubisco homologs grew in CO2 equally or better than the wild-type strain. Our experiments suggest that the primary role of Can carbonic anhydrase during autotrophic growth is for bicarbonate accumulation to support anaplerotic metabolism, and an array of DIC transporters can complement this function. This work demonstrates flexibility in HCO3- uptake and CO2 fixation in C. necator, providing new pathways for CO2-based biomanufacturing. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=166 SRC="FIGDIR/small/593039v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@83c601org.highwire.dtl.DTLVardef@13ca34forg.highwire.dtl.DTLVardef@5b7f8org.highwire.dtl.DTLVardef@1710e48_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗

bioRxiv2023

Lactiplantibacillus plantarum uses ecologically relevant, exogenous quinones for extracellular electron transfer

Extracellular electron transfer (EET) is a metabolic process that frequently uses quinones to couple intracellular redox reactions with extracellular electron acceptors. The physiological relevance of this metabolism for microorganisms that are capable of EET, but unable to synthesize their own quinones, remains to be determined. To address this question, we investigated quinone utilization by Lactiplantibacillus plantarum, a microorganism required for food fermentations, performs EET, and is also a quinone auxotroph. L. plantarum selectively used 1,4-dihydroxy-2-naphthoic acid (DHNA), 2-amino-3-carboxy-1,4-naphthoquinone (ACNQ), 1,4-naphthoquinone, and menadione for EET reduction of insoluble iron (ferrihydrite). However, those quinones used for EET also inhibited L. plantarum growth in non-aerated conditions. Transcriptomic analysis showed that DHNA induced oxidative stress in L. plantarum and this was alleviated by the inclusion of an electron acceptor, soluble ferric ammonium citrate (FeAC), in the laboratory culture medium. The presence of DHNA and FeAC during growth also induced L. plantarum EET metabolism, although activity was still dependent on the presence of exogenous electron shuttles. To determine whether quinone-producing bacteria frequently found together with L. plantarum in food fermentations could be a source of those electron shuttles, L. plantarum EET was measured after incubation with Lactococcus lactis and Leuconostoc mesenteroides. Quinone-producing L. lactis, but not a quinone-deficient L. lactis {Delta}menC mutant, increased L. plantarum ferrihydrite reduction and medium acidification through an EET-dependent mechanism. L. plantarum EET was also stimulated by L. mesenteroides, and this resulted in greater environmental acidification and transient increases in L. plantarum growth. Overall, our findings revealed that L. plantarum overcomes the toxic effects of exogenous quinones to use those compounds, including those made by related bacteria, for EET-conferred, ecological advantages during the early stages of food fermentations.

microbiology↗

bioRxiv2021

Listeria monocytogenes requires cellular respiration for NAD+ regeneration and pathogenesis

Cellular respiration is essential for multiple bacterial pathogens and a validated antibiotic target. In addition to driving oxidative phosphorylation, bacterial respiration has a variety of ancillary functions that obscure its contribution to pathogenesis. We find here that the intracellular pathogen Listeria monocytogenes encodes two respiratory pathways which are partially functionally redundant and indispensable for pathogenesis. Loss of respiration decreased NAD+ regeneration, but this could be specifically reversed by heterologous expression of a water-forming NADH oxidase (NOX). NOX expression fully rescued intracellular growth defects and increased L. monocytogenes loads >1,000-fold in a mouse infection model. Consistent with NAD+ regeneration maintaining L. monocytogenes viability and enabling immune evasion, a respiration-deficient strain exhibited elevated bacteriolysis within the host cytosol and NOX rescued this phenotype. These studies show that NAD+ regeneration, rather than oxidative phosphorylation, represents the primary role of L. monocytogenes respiration and highlight the nuanced relationship between bacterial metabolism, physiology, and pathogenesis.

microbiology↗

bioRxiv2021

Extracellular electron transfer increases fermentation in lactic acid bacteria via a hybrid metabolism

Energy conservation in microorganisms is classically categorized into respiration and fermentation, however recent work shows some species can use mixed or alternative bioenergetic strategies. We explored the utility of a flavin-based extracellular electron transport (FLEET) system for energy conservation within diverse lactic acid bacteria (LAB), microorganisms that mainly rely on fermentative metabolism and are important in food fermentations. The LAB Lactiplantibacillus plantarum uses extracellular electron transfer to increase its NAD+/NADH ratio, generate more ATP through substrate-level phosphorylation and accumulate biomass more rapidly. This novel, hybrid metabolism was dependent on a type-II NADH dehydrogenase (Ndh2) and conditionally required a flavin-binding extracellular lipoprotein (PplA) in the FLEET system to confer increased fermentation yield, metabolic flux, and environmental acidification in both laboratory media and food fermentation. The discovery of a single pathway that blends features of fermentation and respiration expands our knowledge of energy conservation metabolism and provides immediate biotechnology applications.

microbiology↗