Biology subjects

Figueiras, R.

Publications and source records attributed to Figueiras, R..

3 recordsLinked to original sources

bioRxiv2026

Pathogen-dependent biocontrol activity of Chlorella sorokoniana aqueous extracts against fungal and oomycete plant pathogens

Fungal and oomycete plant pathogens are major drivers of yield losses worldwide and are spurring the search for sustainable alternatives to synthetic pesticides. Algae, in general, and microalgae, in particular, represent a promising source of bioactive compounds for crop protection. Despite this, their efficacy across different host-pathogen systems remains poorly characterised. This study evaluated the biocontrol potential of the aqueous extract of Chlorella sorokoniana against three economically important phytopathogens using complementary in vitro, ex vivo, and in planta assays. The strongest activity was observed against Magnaporthe oryzae, with the extract reducing fungal growth by approximately 70% in vitro, inhibiting appressorium formation by 55%, suppressing lesion development on detached rice leaves by more than 75%, and reducing rice blast severity by 64.5% as a preventive foliar treatment. In contrast, the extract showed little or no direct in vitro antifungal activity against Pythium ultimum and Rhizoctonia solani, yet it significantly reduced disease severity in planta by 13-37% and 48-55%, respectively. The contrasting responses among pathosystems suggest that C. sorokoniana aqueous extracts act through different mechanisms depending on the pathogen and the crop, combining direct antifungal activity against M. oryzae with plant-associated protective effects against soil-borne pathogens. These findings highlight the importance of evaluating candidate biocontrol products using complementary in vitro and in planta approaches, as laboratory antimicrobial assays alone may substantially underestimate their agricultural potential. The broad-spectrum protection achieved with an unrefined aqueous extract further supports C. sorokoniana as a promising source of sustainable crop protection products and provides a strong foundation for future mechanistic studies, formulation development, and field validation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/742703v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@428ebaorg.highwire.dtl.DTLVardef@1a85992org.highwire.dtl.DTLVardef@190a605org.highwire.dtl.DTLVardef@183b905_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2025

Organ-specific isolation of hepatocyte extracellular vesicles from human plasma enables tissue-resolved proteomic and miRNA profiling

Tissue-specific resolution remains a key limitation in liquid biopsy to achieve the highest accuracy for precision medicine. To address this limitation, we developed NEXPLOR (Novel EXtracellular vesicle PopuLation and Omics Revealer), a magnetic bead-based platform enabling selective immuno-isolation of tissue-derived EVs. Focusing on hepatocyte-derived EVs (h-EVs), we demonstrate NEXPLORs specificity and sensitivity in capturing rare EV subpopulations directly from human plasma. Using in silico tissue marker discovery, we identified and validated a TOP4 capture antibody panel (ASGR1, ASGR2, TFR2, SLCO1B1) for h-EV isolation through an ultrasensitive orthogonal method (O-NEXOS). Applied to liver disease using clinical plasma samples, NEXPLOR enabled deeper and more reproducible proteomic profiling compared to matched bulk EVs, revealing liver-specific and disease-relevant pathways, including ferroptosis, HIF-1 signaling, and central carbon metabolism in cancer. Moreover, small RNA sequencing uncovered a reduced but highly informative set of miRNAs, including miR-124-3p and miR-23b-3p, differentially expressed in hepatocellular carcinoma (HCC) compared to cirrhosis, and undetectable in bulk EVs. These molecular signatures suggest disease state based on real-time hepatocyte biology. Our findings establish NEXPLOR as a robust platform for tissue-specific EV capture, enabling tissue-resolved, multi-omic biomarker discovery. This opens new frontiers in early disease detection, longitudinal monitoring, and AI-powered biomarker discovery for precision medicine.

molecular biology↗

bioRxiv2022

An electro-optical bead-nanochip technology for the ultrasensitive and multi-dimensional detection of small extracellular vesicles and their markers

Small extracellular vesicles (sEVs), including exosomes, are enriched in multiomics information mirroring their parental cells. They have been investigated in health and disease and utilised in several applications from drug discovery to diagnostics. In disease diagnostics, sEVs can be sampled via a blood draw, enabling the convenient liquid biopsy of the tissue they originate from. However, few applications with sEVs have been translated into clinical practice. We developed a Nanoparticle EXOsome Sensing (NEXOS) technology, for the ultrasensitive and multi-dimensional detection of sEVs. NEXOS comprises two methods: a novel nanoelectronics method, E-NEXOS, and a high-throughput optical detection method, O-NEXOS. Both methods share the same steps for the immunocapture and antibody-labelling of sEVs and can be combined to derive differentiated detection parameters. As a proof of concept, we show the analytical detection and sensitivity of these methods in detecting pre-prepared cancer cell-derived CD9+CD81+ and CD9+HER2+ sEVs. Both sEV populations were diluted in PBS and spiked in processed plasma. We also provide a novel approach for the determination of target sEVs (TEVs), target epitopes in sEVs (TEPs), and epitopes per target sEV, as yet unseen from current and emerging technologies. Further, we demonstrate the higher sensitivity of O-NEXOS compared to the gold standard techniques, as well as demonstrating that E-NEXOS possesses commensurate sensitivity whilst only being powered by 36 nanogap-based sensors per nanochip. Finally, this manuscript lays the groundwork for a scalable electronics miniaturization of E-NEXOS nanochip with millions of nanogap-based sensors for the translation of NEXOS into standard clinical practice.

molecular biology↗