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Candida auris has become a serious threat to public health. The mechanisms of how this fungal pathogen adapts to the mammalian host are poorly understood. Here we report the rapid evolution of an adaptive C. auris multicellular aggregative morphology in the murine host during systemic infection. C. auris aggregative cells accumulate in the brain and exhibit obvious advantages over the single-celled yeast-form cells during systemic infection. Genetic mutations, specifically de novo point mutations in genes associated with cell division or budding processes, underlie the rapid evolution of this aggregative phenotype. Most mutated C. auris genes are associated with the regulation of cell wall integrity, cytokinesis, cytoskeletal properties, and cellular polarization. Moreover, the multicellular aggregates are notably more recalcitrant to the host antimicrobial peptides LL-37 and PACAP relative to the single-celled yeast-form cells. Overall, to survive in the host, C. auris can rapidly evolve a multicellular aggregative morphology via genetic mutations. Bing et al. report that Candida auris undergoes rapid evolution via de novo genetic mutations and forms multicellular aggregates that exhibit a survival advantage over the single-celled yeast-form phenotype during host infection.

Candida auris is a multidrug-resistant human fungal pathogen responsible for nosocomial outbreaks worldwide. Although considerable progress has increased our understanding of the biological and clinical aspects of C. auris , its interaction with the host immune system is only now beginning to be investigated in-depth. Here, we compare the innate immune responses induced by C. auris BJCA001 and Candida albicans SC5314 in vitro and in vivo. Our results indicate that C. auris BJCA001 appears to be less immunoinflammatory than C. albicans SC5314, and this differential response correlates with structural features of the cell wall. Candida auris is a multidrug-resistant human fungal pathogen responsible for nosocomial outbreaks worldwide. Here, the authors identify differential innate immune responses induced by C. auris and Candida albicans in vitro and in vivo, which correlate with structural features of the cell wall.

The rise of drug-resistant fungal species, such as Candida auris , poses a serious threat to global health, with mortality rates exceeding 40% and resistance rates surpassing 90%. The limited arsenal of effective antifungal agents underscores the urgent need for novel strategies. Here, we systematically evaluate the role of histone H3 post-translational modifications in C. auris drug resistance, focusing on acetylation mediated by Gcn5 and Rtt109, and methylation mediated by Set1, Set2, and Dot1. Mutants deficient in these enzymes exhibit varying degrees of antifungal drug sensitivity. Notably, we discover that GCN5 depletion and the subsequent loss of histone H3 acetylation downregulates key genes involved in ergosterol biosynthesis and drug efflux, resulting in increased susceptibility to azoles and polyenes. Additionally, Gcn5 regulates cell wall integrity and echinocandin resistance through the calcineurin signaling pathway and transcription factor Cas5. In infection models using Galleria mellonella and immunocompromised mice, GCN5 deletion significantly reduces the virulence of C. auris . Furthermore, the Gcn5 inhibitor CPTH 2 synergizes with caspofungin in vitro and in vivo without notable toxicity. These findings highlight the critical role of Gcn5 in the resistance and pathogenicity of C. auris , positioning it as a promising therapeutic target for combating invasive fungal infections. In this work, authors show that the key epigenetic regulator Gcn5 contributes to multidrug resistance in Candida auris . The inhibition of its activity by CPTH 2 synergizes with caspofungin, presenting a promising antifungal strategy.

The yeast Candida albicans transitions between distinct lifestyles as a normal component of the human gastrointestinal microbiome and the most common agent of disseminated fungal disease. We previously identified Sef1 as a novel Cys(6)Zn(2) DNA binding protein that plays an essential role in C. albicans virulence by activating the transcription of iron uptake genes in iron-poor environments such as the host bloodstream and internal organs. Conversely, in the iron-replete gastrointestinal tract, persistence as a commensal requires the transcriptional repressor Sfu1, which represses SEF1 and genes for iron uptake. Here, we describe an unexpected, transcription-independent role for Sfu1 in the direct inhibition of Sef1 function through protein complex formation and localization in the cytoplasm, where Sef1 is destabilized. Under iron-limiting conditions, Sef1 forms an alternative complex with the putative kinase, Ssn3, resulting in its phosphorylation, nuclear localization, and transcriptional activity. Analysis of sfu1 and ssn3 mutants in a mammalian model of disseminated candidiasis indicates that these post-transcriptional regulatory mechanisms serve as a means for precise titration of C. albicans virulence.

Meiotic crossovers (COs) are not uniformly distributed across the genome. Factors affecting this phenomenon are not well understood. Although many species exhibit large differences in CO numbers between sexes, sex-specific aspects of CO landscape are particularly poorly elucidated. Here, we conduct high-resolution CO mapping in maize. Our results show that CO numbers as well as their overall distribution are similar in male and female meioses. There are, nevertheless, dissimilarities at local scale. Male and female COs differ in their locations relative to transcription start sites in gene promoters and chromatin marks, including nucleosome occupancy and tri-methylation of lysine 4 of histone H3 (H3K4me3). Our data suggest that sex-specific factors not only affect male–female CO number disparities but also cause fine differences in CO positions. Differences between male and female CO landscapes indicate that recombination has distinct implications for population structure and gene evolution in male and in female meioses. Sex-specific meiotic crossover (CO) landscapes have been identified in multiple species. Here, the authors show that male and female meioses in maize have similar CO landscapes, and differences between COs in the two sexes only exists in their location relative to transcription start sites and some chromatin marks.

Bacteria–fungi interactions play crucial roles in shaping microbial communities across diverse environmental and host-associated niches. While their antagonism through diffusible metabolites is a well-known ecological phenomenon, delivery of bacterial effectors into the nucleus of fungal cells remains rare, and the mechanisms are poorly understood. Here, we identify and characterize a potent anti-fungal nuclease effector, TseN, delivered by the type VI secretion system (T6SS) of Acidovorax citrulli . TseN possesses a nuclear localization signal and inhibits multiple fungal species, including emerging human pathogens Candida auris and Cryptococcus neoformans . Structural and biochemical analyses show that TseN possesses a unique C-terminal DNase domain that defines a new effector class, with its activity neutralized by a cognate immunity protein TsiN. The delivery of TseN requires the upstream-encoded VgrG5, a chaperone Aave_2128, and PAAR5. Transcriptome profiling of co-cultured bacterial-fungal cells demonstrates that the T6SS attack triggers extensive reprogramming in fungal cells, affecting DNA repair, stress response, and filamentation pathways. These responses not only compromise fungal survival but also modulate fungal drug resistance, as evidenced by the synergistic enhancement of azole efficacy against drug-resistant Candida albicans . Importantly, in vivo experiments confirm that the T6SS, via TseN, can significantly reduce fungal burden on murine skin. Phylogenetic analysis shows TseN homologs are present in a large number of bacterial species. Collectively, our findings highlight a previously underappreciated interkingdom antagonism modulated by a novel effector. The broad-spectrum anti-fungal activities of TseN and its homologs may be explored for therapeutic strategies targeting fungal pathogens in both clinical and environmental settings.

As a clinically relevant opportunistic human fungal pathogen, Candida albicans is able to rapidly sense and adapt to changing microenvironments within the host, a process that is essential for its successful invasion and survival. Although studies have shown that the transcription factor Stp2 is the master regulator of environmental alkalinization, accumulating evidence supports a clear involvement of other participants in this adaptation process. Here, following a large-scale genetic screen, we identify the transcription factor Dal81 as an uncharacterized positive regulator of pH alkalinization in C. albicans . Dal81 influences the protein levels of Stp2. A mutant lacking DAL81 also fails to alkalinize both in vitro and in the phagolysosome, and this defective phenotype is further enhanced by deleting both factors in most cases. Notably, our results demonstrate that Dal81 physically interacts with Stp2 to co-regulate the expression of a broad set of downstream target genes related to metabolism of organic acids, oxoacids, carboxylic acids and amino acids. This coordinated regulation mode is required for the alkalinization process and plays a role in modulating commensalism and pathogenicity of C. albicans . Taken together, our findings elucidate the cooperative function of Dal81 with Stp2 in the nucleus to orchestrate the expression of downstream genes required for the survival and propagation of C. albicans in the host. In this work, authors perform a large-scale genetic screen to explore the previously unrecognized physical interaction between two transcription factors in Candida albicans . The roles of Stp2 and Dal81 are important in extracellular pH alkalization, fitness, and pathogenicity, key processes requiring coordinated gene regulatory networks governing amino acid metabolism.

Background Tuberculosis (TB) had been the leading lethal infectious disease worldwide for a long time (2014–2019) until the COVID-19 global pandemic, and it is still one of the top 10 death causes worldwide. One important reason why there are so many TB patients and death cases in the world is because of the difficulties in precise diagnosis of TB using common detection methods, especially for some smear-negative pulmonary tuberculosis (SNPT) cases. The rapid development of metabolome and machine learning offers a great opportunity for precision diagnosis of TB. However, the metabolite biomarkers for the precision diagnosis of smear-positive and smear-negative pulmonary tuberculosis (SPPT/SNPT) remain to be uncovered. In this study, we combined metabolomics and clinical indicators with machine learning to screen out newly diagnostic biomarkers for the precise identification of SPPT and SNPT patients. Methods Untargeted plasma metabolomic profiling was performed for 27 SPPT patients, 37 SNPT patients and controls. The orthogonal partial least squares-discriminant analysis (OPLS-DA) was then conducted to screen differential metabolites among the three groups. Metabolite enriched pathways, random forest (RF), support vector machines (SVM) and multilayer perceptron neural network (MLP) were performed using Metaboanalyst 5.0, “caret” R package, “e1071” R package and “Tensorflow” Python package, respectively. Results Metabolomic analysis revealed significant enrichment of fatty acid and amino acid metabolites in the plasma of SPPT and SNPT patients, where SPPT samples showed a more serious dysfunction in fatty acid and amino acid metabolisms. Further RF analysis revealed four optimized diagnostic biomarker combinations including ten features (two lipid/lipid-like molecules and seven organic acids/derivatives, and one clinical indicator) for the identification of SPPT, SNPT patients and controls with high accuracy (83–93%), which were further verified by SVM and MLP. Among them, MLP displayed the best classification performance on simultaneously precise identification of the three groups (94.74%), suggesting the advantage of MLP over RF/SVM to some extent. Conclusions Our findings reveal plasma metabolomic characteristics of SPPT and SNPT patients, provide some novel promising diagnostic markers for precision diagnosis of various types of TB, and show the potential of machine learning in screening out biomarkers from big data.

Candida albicans , the primary etiology of human mycoses, is well-adapted to catabolize proline to obtain energy to initiate morphological switching (yeast to hyphal) and for growth. We report that put1-/- and put2-/- strains, carrying defective P roline UT ilization genes, display remarkable proline sensitivity with put2 -/- mutants being hypersensitive due to the accumulation of the toxic intermediate pyrroline-5-carboxylate (P5C), which inhibits mitochondrial respiration. The put1-/ - and put2-/- mutations attenuate virulence in Drosophila and murine candidemia models and decrease survival in human neutrophils and whole blood. Using intravital 2-photon microscopy and label-free non-linear imaging, we visualized the initial stages of C . albicans cells infecting a kidney in real-time, directly deep in the tissue of a living mouse, and observed morphological switching of wildtype but not of put2-/- cells. Multiple members of the Candida species complex, including C . auris , are capable of using proline as a sole energy source. Our results indicate that a tailored proline metabolic network tuned to the mammalian host environment is a key feature of opportunistic fungal pathogens.

Meiotic recombination is the most important source of genetic variation in higher eukaryotes. It is initiated by formation of double-strand breaks (DSBs) in chromosomal DNA in early meiotic prophase. The DSBs are subsequently repaired, resulting in crossovers (COs) and noncrossovers (NCOs). Recombination events are not distributed evenly along chromosomes but cluster at recombination hotspots. How specific sites become hotspots is poorly understood. Studies in yeast and mammals linked initiation of meiotic recombination to active chromatin features present upstream from genes, such as absence of nucleosomes and presence of trimethylation of lysine 4 in histone H3 (H3K4me3). Core recombination components are conserved among eukaryotes, but it is unclear whether this conservation results in universal characteristics of recombination landscapes shared by a wide range of species. To address this question, we mapped meiotic DSBs in maize, a higher eukaryote with a large genome that is rich in repetitive DNA. We found DSBs in maize to be frequent in all chromosome regions, including sites lacking COs, such as centromeres and pericentromeric regions. Furthermore, most DSBs are formed in repetitive DNA, predominantly Gypsy retrotransposons, and only one-quarter of DSB hotspots are near genes. Genic and nongenic hotspots differ in several characteristics, and only genic DSBs contribute to crossover formation. Maize hotspots overlap regions of low nucleosome occupancy but show only limited association with H3K4me3 sites. Overall, maize DSB hotspots exhibit distribution patterns and characteristics not reported previously in other species. Understanding recombination patterns in maize will shed light on mechanisms affecting dynamics of the plant genome.