Browse Articles

Assessing the potential for biogeochemical deterioration of building materials by green algae in temperate climate via an integrated metabolomic approach

Abstract Biodeterioration of building materials by aerophytic green algae is increasingly recognized as a significant factor affecting the aesthetic value and durability of brick and plaster façades, yet the biochemical mechanisms underlying this process remain poorly understood. This study investigates the metabolomic profiles of five algal taxa: Chloroidium saccharophilum PNK010, Klebsormidium nitens PNK013, Bracteacoccus minor PNK015, Diplosphaera chodatii PNK021, and Stichococcus bacillaris PNK040 growing on brick and plaster for a year under laboratory and environmental conditions. Untargeted UHPLC–MS/MS metabolomics, with metabolic pathway and chemical-class enrichment analyses, were used to characterize substrate- and condition-associated metabolic signatures and to detect metabolites potentially involved in material deterioration. The research demonstrated strain-specific and substrate-driven metabolic differentiation. Plaster exhibited higher metabolic heterogeneity and stress-related pathways, whereas brick showed more conserved, growth-associated metabolic profiles. Across taxa, low-molecular-weight organic acids, including citric/isocitric, acetic, and oxalic, were recurrently detected, suggesting their potential involvement in acidification- and metal-complexation-related processes at the algal–mineral interface. Enrichment of flavin nucleotides, carboxylic acids, fatty acyls, and aromatic secondary metabolites further supports the involvement of redox activity, stress adaptation, and biofilm persistence. These findings allow a provisional ranking of the algae based on their potential for geochemical biodeterioration, as follows: PNK010 > PNK040> PNK015 > PNK021> PNK013.

Paleorecords inform the limits of Indo-Pacific coral reef survival under accelerating sea-level rise

A pilot study on aging-related effects on step performance: The role of muscle quality, size, and strength

All-2D vertical metal-semiconductor field-effect transistor with sub-10 nm channel and contact lengths

Indices of trophic and competitive relationships in a planktonic meta-network of carp ponds

Conformational cycling of the Wntless transporter drives trafficking and secretion of Wnt morphogens

Abstract Wnt proteins are lipid-modified morphogens fundamental in development and disease. During Wnt biogenesis, the G-protein-coupled receptor (GPCR)-like transporter Wntless (WLS) escorts lipidated Wnts from the endoplasmic reticulum to the plasma membrane, then transfers them to extracellular carriers, forming active and soluble morphogen-carrier complexes. To dissect the mechanisms involved, we solve cryo-EM structures of Wnt-bound WLS and unliganded WLS, and perform structure-guided functional experiments. Wnts engage WLS via three conserved hairpins, which are all required for Wnt trafficking to the cell surface and carrier-mediated secretion. Wnt release from cells is driven by dramatic conformational changes in the WLS transmembrane domain, reminiscent of GPCR activation, together with WLS extracellular rearrangements. Unexpectedly, we find that Wnt5a bound to WLS forms dimers, with implications for Wnt signaling. These findings define the mechanism of WLS conformational cycling that governs the intracellular transport and extracellular release of Wnt morphogens, essential steps in the Wnt pathway.

Co-occurrence of uranium, fluoride and nitrate in Sahelian groundwater of Agadez (Niger) drives population health risks

Molecular mechanisms of transhydrogenase activity and allosteric regulation in eukaryotic type II PHGDH Ser33

Abstract L-serine is a critical structural constituent of proteins and membrane phospholipids, playing major roles in cell signaling, metabolism and development. L-Serine is synthesized through a conserved de novo pathway starting from the glycolytic intermediate 3-phosphoglycerate (PGA), being oxidized by 3-phosphoglycerate dehydrogenase (PHGDH) into 3-phosphohydroxypyruvate (PHP). In certain organisms, PHGDH operates as a transhydrogenase using α-ketoglutarate rather than NAD + as the final electron acceptor and producing both PHP and D-2-hydroxyglutarate (2HG). We provide high-resolution X-ray crystal structures of the transhydrogenase Ser33 from Saccharomyces cerevisiae , in complex with the cofactor NADH, and with PGA, PHP, 2HG and the negative allosteric regulator L-serine. Combining extensive alanine scanning mutagenesis, enzyme activity assays and kinetics, molecular dynamics simulations, biophysical methods, and phylogenetic analysis, we establish the molecular basis of substrate recognition, transhydrogenase activity, and allosteric inhibition mechanisms, including the role of an N-terminal extension in the regulation of eukaryotic Type II PHGDHs.

Assessing county-level high-quality development and spatial adaptation paths under the space of flows perspective: a coupling detrended fluctuation analysis approach

A domestication gene links plant architecture and nitrogen metabolism to enhance yield in foxtail millet

Allicin-loaded soluplus polymeric micelles differentially modulate doxorubicin response in adenocarcinoma and myocardial cell models

Scaling covalent ligand discovery through dynamic combinatorial library-versus-proteome screening

The effect of customer incivility on proactive customer service performance mediated by emotional exhaustion and moderated by proactive personality

Multiplexed cytokine and antigen mRNA administration generates durable anti-tumor immunity against pancreatic cancer

Methylprednisolone for heart surgery in pediatric patients: a meta-analysis of randomized trials

Enabling high-voltage aqueous dual-ion batteries capable of working at −40 °C in a low-concentration salt electrolyte

Compound hydrogeomorphic cascades and rapid upstream to downstream hazard coupling in the Eastern Himalaya

Disruption of the brain-spleen axis impairs monocyte-microglia communication and accelerates disease progression in a mouse model of amyloidosis

Correlation between fecal eosinophil cationic protein and cow’s milk protein allergy in extremely preterm infants and its value in auxiliary diagnosis

A cyclin-polarity feedback network ensures healthy cell proliferation

Abstract Healthy proliferation requires the coordination of cell cycle progression with cell polarity. In budding yeast, polarity is established when G1-cyclin-Cdc28 Cdk1 triggers Cdc42 activation to generate a cell pole that is used as an axis for growth and division. While polarity defects delay the cell cycle temporally, permitting error correction, it is unknown if Cdc28 Cdk1 directly rectifies errant polarity. Here, we identify an adaptive response where G1-cyclin-Cdc28 Cdk1 participates in error correction via the augmentation of its kinase activity towards substrates that activate Cdc42. The response involves temporal and spatial cell cycle reconfiguration via extended G1 cyclin expression, nucleocytoplasmic rerouting and signaling. However, this strategy has a cost: if the defect is irreparable, high G1-cyclin levels enforce inexorable cell cycle commitment in the absence of a daughter cell, generating multinucleate cells. G1-cyclins therefore not only trigger G1 events, but also monitor their execution, employing feedback to coordinate polarity with cell cycle progression.