Hassan, M. I. | bioRxiv Science

bioRxiv2026

Interaction Patterns of Mucormycotina Fungi with Professional Phagocytes and Amoebae: A Comparative Phylogenetic and Geographic Survey on Clinical and Environmental Species

Mucormycosis is among the most lethal fungal infections in clinical medicine, with crude mortality rates between 50 and 90% that have improved little over decades of antifungal development. Alveolar macrophages constitute the primary cellular defense against inhaled Mucorales spores, yet quantitative comparative data on phagocytic outcomes across the taxonomic breadth of this fungal order are absent from the literature. We co-incubated 62 Mucorales strains drawn from nine phylogenetic groups and 12 countries with MH-S murine alveolar macrophages and with Dictyostelium discoideum amoeba, at multiplicities of infection (MOI) of 1 and 5 and at incubation times of 1.5 and 3 hours. Automated phagocytic index quantification was combined with spore morphometric measurements and geographic metadata. Macrophage phagocytic indices differed highly significantly among the nine phylogenetic groups across all experimental conditions (Kruskal-Wallis H = 394-780; p = 10^-163 to 10^-74). Group 1 (Absidia and Cunninghamella species) showed the lowest phagocytic index; Groups 5 (Rhizopus arrhizus) and 6 (Gilbertella persicaria and Mycotypha species) showed the highest. Larger spore area correlated negatively with macrophage phagocytic index. In the central comparative finding, Spearman rank correlations between macrophage and D. discoideum phagocytic indices were near zero across all four conditions (r = -0.07 to +0.11; all p > 0.8), demonstrating that protozoan phagocytosis does not predict the mammalian macrophage phagocytic hierarchy. Kinetic analysis further revealed, for the first time in any Mucorales or Mucormycotina species, evidence of vomocytosis in MH-S macrophages challenged with Group 8 (Mucor clade II) spores at MOI 1, and in D. discoideum across four groups at MOI 5 after 3 hours. These findings establish a quantitative, phylogenetically resolved framework for Mucorales innate immune recognition, demonstrate that the evolutionary training ground hypothesis does not hold at the order level for Mucorales, and identify vomocytosis as a previously unrecognised immune evasion mechanism in Mucormycotina.

microbiology↗

bioRxiv2018

Structural and functional impact of non- synonymous SNPs in the CST complex subunit TEN1: Structural genomics approach

TEN1 protein is a key component of CST complex, implicated in maintaining the telomere homeostasis, and provide stability to the eukaryotic genome. Mutations in TEN1 gene have higher chances of deleterious impact; thus, interpreting the number of mutations and their consequential impact on the structure, stability and function is essentially important. Here, we have investigated the structural and functional consequences of nsSNPs in the TEN1 gene. A wide array of sequence- and structure-based computational prediction tools were employed to identify the effects of 78 nsSNPs on the structure and function of TEN1 protein and deleterious nsSNPs were identified. These deleterious or destabilizing nsSNPs are scattered throughout the structure of TEN1. However, major mutations were observed in the 1-helix (12-16) and {beta}5-strand (88-96). We further observed that mutations at C-terminal region were have higher tendency to form aggregate. In-depth structural analysis of these mutations reveals that the pathogenecity of these mutations are driven mainly through larger structural changes because of alterations in non-covalent interactions. This work provides a blue print to pinpoint the possible consequences of pathogenic mutations in the CST complex subunit TEN1.

evolutionary biology↗