Journal: bioRxiv

Article Title: Dynamic Reprogramming of Fungal Cell Walls Underlies Germination and Immune Exposure in Zygomycetous Fungal Pathogens

doi: 10.64898/2026.05.12.724644

Figure Lengend Snippet: ( A ) TEM images of the dormant conidia reveal a multilayered cell wall architecture, including an electron-dense outer layer and inner polysaccharide-rich regions. ( B ) At high magnification, osmium-fixed, epoxy-embedded samples (left) preserve structural integrity, whereas LR White–embedded samples prepared without OsO 4 (right) enhance contrast in the outer wall. Sub-labels denote (i) outer electron-dense region, (ii) granular region, and (iii) electron-lucent inner layer. Without OsO 4 , the outer layer appears as a thin electron-lucent band consistent with melanin, with the remaining regions largely electron-lucent. ( C ) Rigid molecules in the dormant conidial cell walls were detected by 2D 13 C- 13 C CORD spectra, showing signals from β-1,3-glucan (B), chitin (Ch), and chitosan (Cs). Superscripts indicate different structural forms of each polysaccharide, and the numbers denote carbon positions. For example, Cs a 1-2 represents the correlation between carbons 1 and 2 in type-a chitosan. ( D ) Structural representations of carbohydrates. Yellow bars indicate whether each molecule is detected in the rigid phase, the mobile phase, or in both. NMR abbreviations are given. Key carbon sites are numbered. ( E ) Composition of rigid carbohydrates in dormant conidia based on intensity analysis of the 2D CORD spectrum. ( F ) Overlay of 2D CORD spectra of dormant conidia (blue) and 3-day-old mycelia (orange). ( G ) Cytochemical labeling of dormant conidia shows gold-specific staining for β-1,3-glucan with Fc-Dectin-1, chitin (with Wheat germ agglutinin lectin (WGA-lectin), and anti-chitosan rabbit antiserum. Black dots represent electron-dense gold particles indicating probe binding. Scale bars: 500 nm. ( H ) Mobile molecules in dormant conidia detected by the 2D 13 C-DP refocused J-INADEQUATE spectrum. In addition to β-1,3-glucan and two forms of chitosan, signals are detected for Fuc (F), Gal, α-1,2-Man (Mn , ), and α-1,6-Man (Mn , ). ( I ) Cytochemical binding of Concanavalin-A lectin (ConA) to dormant conidial cell walls confirms the presence of mannans and/or glycoproteins. Zoomed-in view of 2D 13 C-DP J-INADEQUATE spectrum was presented for ( J ) C5-C6 correlations of polymeric fucoses and ( K ) glucuronic acid (GlcA). Polymeric fucoses show five forms (a,b, c, d, i) as traced by dashed lines in dormant conidia (blue) while type-e is present only in mycelia (orange).

Article Snippet: Grids were washed with endotoxin-free water and incubated for 1 h with 100 μg mL -1 recombinant human Fc-Dectin-1 (Fc-hDectin-1a, InvivoGen).

Techniques: Labeling, Staining, Binding Assay

Journal: bioRxiv

Article Title: Dynamic Reprogramming of Fungal Cell Walls Underlies Germination and Immune Exposure in Zygomycetous Fungal Pathogens

doi: 10.64898/2026.05.12.724644

Figure Lengend Snippet: ( A ) TEM images of germinating conidia showing swollen conidia undergoing isotropic expansion at 1 h (left), swollen conidia with rupture of the outer cell wall enabling emergence of a polarized germ tube (middle), and elongated germ tubes (right). Magenta arrows indicate changes in the outer wall, while yellow arrows highlight the thinner inner layer that extends and contributes to germ tube wall formation. ( B ) Violin plot showing the reduction in cell wall thickness from dormant conidia (DC) to swollen (SW) and germ tube (GT) stages (n=120 per group). ( C ) 1D 13 C CP spectra detecting only neosynthesized polysaccharides in germinating 12 C-conidia grown in 13 C-labeled media (inset). Spectra were collected at different time points of 1 h (black), 2.5 h (green), and 5 h (magenta). Dashed lines highlight the signature peaks of chitin, β-1,3-glucan, and chitosan. ( D ) Molar composition of rigid neo-synthesized polysaccharides (%) in the 1-5 h culture. Compositional percentages are calculated by deconvoluting 1D 13 C CP spectra. ( E ) 2D 13 C- 13 C CORD spectra of the 5 h culture, with blue circles indicating the absence of β-1,3-glucan signals. ( F ) Cytochemical labeling of gold-specific staining for β-1,3-glucan (with Fc-Dectin-1, top), chitin (with WGA-lectin, middle), and anti-chitosan rabbit antiserum (bottom). Scale bars: 500 nm. Electron-dense gold particles (black dots) mark probe binding. The newly formed thin cell wall of germ tube (orange arrowheads) is labeled by WGA and anti-chitosan. Dectin labeling is only positive in the cell wall of the original resting conidium cell wall. Magenta arrows indicate the location of outer wall changes, and yellow arrows highlight the extending inner layer contributing to germ tube formation.

Article Snippet: Grids were washed with endotoxin-free water and incubated for 1 h with 100 μg mL -1 recombinant human Fc-Dectin-1 (Fc-hDectin-1a, InvivoGen).

Techniques: Labeling, Synthesized, Staining, Binding Assay

Journal: Frontiers in Microbiology

Article Title: ULK1 mediated autophagy in airway cells during Aspergillus infection

doi: 10.3389/fmicb.2026.1756294

Figure Lengend Snippet: Model of a novel ULK1-mediated LAP-like pathway in airway cells during A. fumigatus conidial internalization. During the interaction between A. fumigatus conidia and airway cells, several changes occur: intracellular LC3-II levels, phosphorylation of AMPK and ULK1, and reactive oxygen species (ROS) content all increase. Additionally, the release of cytokines—including IL-6, IL-8, and MCP-1—also rises. Inhibiting ULK1 activity or silencing its expression can suppress the increase in LC3-II levels and cytokine release triggered by A. fumigatus . Notably, common fungal polysaccharides and Dectin-1 did not impact this process, but the loss of complement receptor 3 elevated both basal and conidia-induced autophagy, correlating with increased AMPK expression. Dashed lines indicate signal pathway interactions hypothesized to occur in airway cells.

Article Snippet: LC3 Rabbit Polyclonal antibody(#14600-1-AP, 1:1000), Rubicon Rabbit Polyclonal Antibody (#21444-1-AP, 1:1000), GAPDH Polyclonal antibody(#10494-1-AP, 1:2000) were purchased from proteintech, Phospho-UKL1(Ser555) Rabbit monoclonal antibody (#5869, 1:500), Phospho-UKL1(Ser757) Rabbit monoclonal antibody (#6888, 1:500), ULK1 rabbit monoclonal antibody (#8054, 1:1000), SQSTM1/p62 antibody (#5114, 1:1000), Atg5 Rabbit monoclonal antibody (#12994, 1:1000), Dectin-1 Rabbit monoclonal antibody (#60128, 1:1000), AMPKalpha Antibody (#2532, 1:1000), Phospho-AMPKalpha (Thr172) Rabbit monoclonal antibody(#50081, 1:1000), β -tubulin Rabbit monoclonal antibody(#2128, 1:2000) were purchased from Cell Signaling Technology (USA).

Techniques: Phospho-proteomics, Activity Assay, Expressing