Extracellular polysaccharide production by marine diatoms is a significant route by which photosynthetically produced organic carbon enters the trophic web and may influence the physical environment in the sea. This study highlights the capacity of atomic force microscopy (AFM) for investigating diatom extracellular polysaccharides with a subnanometer resolution. Here we address a ubiquitous marine diatom Cylindrotheca closterium, isolated from the northern Adriatic Sea, and its extracellular polymeric substance (EPS) at a single cell level. We applied a simple procedure for AFM imaging of diatom cells on mica under ambient conditions (in air) to achieve visualization of their EPS with molecular resolution. The EPS represents a web of polysaccharide fibrils with two types of cross-linking: fibrils association forming junction zones and fibril-globule interconnections with globules connecting two or more fibrils. The fibril heights were 0.4-2.6 nm while globules height was in the range of 3-12 nm. Polymer networks of native gel samples from the Northern Adriatic and the network formed by polysaccharides extracted from the C. closterium culture share the same features regarding the fibril heights, pore openings and the mode of fibril association, proving that the macroscopic gel phase in the Northern Adriatic can be formed directly by the self-assembly of diatom released polysaccharide fibrils.
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http://dx.doi.org/10.1002/jmr.1114 | DOI Listing |
Harmful Algae
November 2024
National Institute of Biology, Departments of Biotechnology and Systems Biology, Ljubljana, Slovenia. Electronic address:
Algal blooms impact trophic interactions, community structure and element fluxes. Despite playing an important role in the demise of phytoplankton blooms, only few viruses infecting diatoms have been cultured. Pseudo-nitzschia is a widespread diatom genus that commonly blooms in coastal waters and contains toxin-producing species.
View Article and Find Full Text PDFInt J Hyg Environ Health
January 2025
Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy.
Background: Trace elements, including zinc (Zn) and copper (Cu), although toxic at higher concentrations are known to play important roles in the maintenance of human health and neurodevelopment. Few epidemiological studies have investigated the association between prenatal or early postnatal Cu and Zn levels and child neurodevelopment. The aim of this research is to assess the association between child neurodevelopment at 18 months of age and cord blood and breast milk concentrations of Cu and Zn in Italian mother-child pairs enrolled in the Italian Northern Adriatic Cohort II (NAC-II), a part of the "Public health impact of long-term, low-level, mixed element exposure in susceptible population strata" project PHIME.
View Article and Find Full Text PDFMar Environ Res
November 2024
Department of Life Sciences, University of Trieste, Via L. Giorgieri, 10, 34127, Trieste, Italy.
Assessing historical changes in marine biodiversity at regional or local scales is often challenging due to insufficient long-term data for most marine organisms. Yet, these assessments are crucial to understanding potential long-term variation in the species pool in response to complex and interacting local and global environmental changes. Here, we performed a comprehensive review of scientific and grey literature, archival records and floristic data spanning over the last two centuries to reconstruct an updated and revised taxonomic dataset of macroalgae in the Gulf of Trieste (Northern Adriatic Sea), one of the most exposed to human-driven pressures and climatically vulnerable regions in the Mediterranean Sea.
View Article and Find Full Text PDFEnviron Res
January 2025
Department of Environmental Sciences, Informatic, And Statistics, Ca' Foscari university Venice, Via Torino 155, 30172 Venezia-Mestre, Italy; Società Estense Servizi Ambientali (S.E.S.A. S.p.A.), 35042 EsteItaly.
BMC Plant Biol
October 2024
Institute for Adriatic Crops and Karst Reclamation, Split, Croatia.
Background: Croatia is a geographically small country with a remarkable diversity of cultivated and spontaneous grapevines. Local germplasm has been characterised by microsatellite markers, but a detailed analysis based on single nucleotide polymorphisms (SNPs) is still lacking. Here we characterize the genetic diversity of 149 accessions from three germplasm repositories and four natural sites using 516,101 SNPs to identify complete parent-offspring trios and their relations with spontaneous populations, offering a proof-of-concept for the use of reduced-representation genome sequencing in population genetics and genome-wide association studies (GWAS).
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