Survival at host temperature is a critical trait for pathogenic microbes of humans. Thermally dimorphic fungal pathogens, including Histoplasma capsulatum, are soil fungi that undergo dramatic changes in cell shape and virulence gene expression response to temperature. How these organisms link both morphologic development traits unknown. Here we elucidate temperature-responsive transcriptional network H. which switches from filamentous form the environment yeast body The circuit driven by...

ABSTRACT Histoplasma capsulatum is a fungal pathogen that infects both healthy and immunocompromised hosts. In regions where it endemic, H. grows in the soil causes respiratory systemic disease when inhaled by humans. An interesting aspect of biology adopts specialized developmental programs response to its environment. soil, as filamentous chains cells (mycelia) produce asexual spores (conidia). When disrupted, conidia aerosolize are mammalian Inside host, germinate into yeast-form colonize...

Abstract Background Coccidioides, a dimorphic fungus endemic to the Southwest United States, causes unacceptably high morbidity/mortality. Coccidioides’ virulence stems from its unique and poorly understood host form, spherule. Spores are inhaled by develop into spherules, which mature until they fill with hundreds of endospores then rupture, disseminating throughout host. This entire process is known as spherulation. As spherules most spherule biology remains unknown. Coccidioides genomes...

Abstract Background In the environment, fungal pathogen Coccidioides grows as hyphae, yet when its spores (arthroconidia) are inhaled by a host, they develop instead into parasitic form called spherule. Spherules can be elicited in vitro presence of specific media, elevated temperatures, and high CO2, what triggers this transition vivo role host immune cells remains largely unknown. Methods We performed live imaging posadasii Silveira arthroconidia or absence murine bone marrow derived...

Eukaryotic cells integrate layers of gene regulation to coordinate complex cellular processes; however, mechanisms post-transcriptional remain poorly studied. The human fungal pathogen Histoplasma capsulatum (Hc) responds environmental or host temperature by initiating unique transcriptional programs specify multicellular (hyphae) unicellular (yeast) developmental states that function in infectivity pathogenesis, respectively. Here we used recent advances next-generation sequencing uncover a...

Coccidioides spp. are mammalian fungal pathogens endemic to the Southwestern US and other desert regions of Mexico, Central South America, with bulk infections occurring in California Arizona. In soil, grows a hyphal form that differentiates into 3-5 micron asexual spores (arthroconidia). When arthroconidia inhaled by mammals they undergo unique developmental transition from polar growth isotropic expansion multiple rounds nuclear division, prior segmentation, forming large spherules filled...

Histoplasma capsulatum, a dimorphic fungal pathogen, is the most common cause of respiratory infections in immunocompetent hosts. endemic Ohio and Mississippi River Valleys United States also distributed worldwide. Previous studies have revealed at least eight clades, each specific to geographic location: North American classes 1 2 (NAm NAm 2), Latin groups A B (LAm LAm B), Eurasian, Netherlands, Australian African, an additional distinct lineage (H81) comprised Panamanian isolates....

Phenotypic switching between 2 opposing cellular states is a fundamental aspect of biology, and fungi provide facile systems to analyze the interactions regulons that control this type switch. A long-standing mystery in fungal pathogens humans how thermally dimorphic switch their developmental form response temperature. These fungi, including subject study, Histoplasma capsulatum, are temperature-responsive organisms utilize unknown regulatory pathways couple cell shape associated attributes...

Intracellular pathogens secrete effectors to manipulate their host cells. Histoplasma capsulatum (Hc) is a fungal intracellular pathogen of humans that grows in yeast form the host. Hc yeasts are phagocytosed by macrophages, where replication precedes macrophage lysis. The most abundant virulence factor secreted cells Calcium Binding Protein 1 (Cbp1), which absolutely required for Here we take an evolutionary, structural, and cell biological approach understand Cbp1 function. We find present...

The rat kangaroo (long-nosed potoroo, Potorous tridactylus) is a marsupial native to Australia. Cultured kidney epithelial cells (PtK) are commonly used study cell biological processes. These mammalian large, adherent, and flat, contain large few chromosomes—and thus ideal for imaging intra-cellular dynamics such as those of mitosis. Despite this, neither the genome nor transcriptome have been sequenced, creating challenge probing molecular basis these cellular dynamics. Here, we present...

The fungal pathogen Histoplasma capsulatum ( Hc ) invades, replicates within, and destroys macrophages. To interrogate the molecular mechanisms underlying this interaction, we conducted a host-directed CRISPR-Cas9 screen identified 361 genes that modify macrophage susceptibility to infection, greatly expanding our understanding of host gene networks targeted by . We pathways have not been previously implicated in interaction with macrophages, including ragulator complex (involved nutrient...

The Escherichia coli aspartate (AATase) and tyrosine (TATase) aminotransferases share 43% sequence identity 72% similarity, but AATase has only 0.08% 0.01% of the TATase activities (k(cat)/K(m)) for phenylalanine, respectively. Approximately 5% activity was introduced into framework earlier both by rational design (six mutations, termed HEX) directed evolution (9-17 mutations). enzymes realized from latter procedure complement auxotrophy in deficient E. coli. HEX complements even more poorly...

Abstract Coccidioides spp . are part of a group thermally dimorphic fungal pathogens, which grow as filamentous cells (hyphae) in the soil and transform to different morphology upon inhalation into host. The host form, spherule, is unique highly under characterized due both technical biocontainment challenges. Each spherule arises from an environmental spore (arthroconidium), matures, develops hundreds internal endospores, released rupture. endospore can then go on form another cycle called...

The unfolded protein response (UPR) maintains folding homeostasis in the endoplasmic reticulum (ER). In metazoan cells, Ire1 branch of UPR initiates two functional outputs—non-conventional mRNA splicing and selective decay (RIDD). By contrast, orthologs from Saccharomyces cerevisiae Schizosaccharomyces pombe are specialized for only or RIDD, respectively. Previously, we showed that specialization lies Ire1’s RNase activity, which is either stringently splice-site specific promiscuous (Li et...

Histoplasma is a primary fungal pathogen with the ability to infect otherwise healthy mammalian hosts, causing systemic and sometimes life-threatening disease. Thus far, molecular genetic manipulation of this organism has utilized RNA interference, random insertional mutagenesis, homologous recombination protocol that highly variable often inefficient. Targeted gene manipulations have been challenging due poor rates events in Histoplasma. Interrogation virulence strategies would be...

The fungal pathogen Histoplasma capsulatum is thought to be the most common cause of respiratory infections in immunocompetent humans, yet little known about its biology. Here we provide first genome-wide studies experimentally validate genome annotation. A functional interrogation provides critical support for continued investigation into biology and pathogenesis H. related fungi.We employed a three-pronged approach annotation G217B strain. First, probed high-density tiling arrays with...

Abstract Pathogens often secrete proteins or nucleic acids that mimic the structure and/or function of molecules expressed in their hosts. Molecular mimicry empowers pathogens to subvert critical host processes and establish infection. We report intracellular bacterium Legionella pneumophila secretes toxin SidI (substrate icm/dot transporter I), which possesses a transfer RNA (tRNA)-like shape functions as mannosyl transferase. The 3.1 Å cryo-EM reveals an N-terminal domain exhibits...

ABSTRACT Phenotypic switching between two opposing cellular states is a fundamental aspect of biology, and fungi provide facile systems to analyze the interactions regulons that control this type switch. A long-standing mystery in fungal pathogens humans how thermally dimorphic switch their developmental form response temperature. These fungi, including subject study, Histoplasma capsulatum , are temperature-responsive organisms utilize unknown regulatory pathways couple cell shape...

Comprehensively assess the humoral immune response to Coccidioides infection using a new high-resolution, proteome-wide antibody profiling assay in patients with and without coccidioidal meningitis.

Next generation sequencing has unlocked a wealth of genotype information for microbial populations, but phenotyping remains bottleneck exploiting this information, particularly pathogens that are difficult to manipulate. Here, we establish method high-throughput mixed cultures, in which the pattern naturally occurring single-nucleotide polymorphisms each isolate is used as intrinsic barcodes can be read out by sequencing. We demonstrate our correctly deconvolute strain proportions simulated...

Abstract Coccidioides spp . are highly understudied but significant dimorphic fungal pathogens that can infect both immunocompetent and immunocompromised people. In the environment, they grow as multicellular filaments (hyphae) produce vegetative spores called arthroconidia. Upon inhalation by mammals, arthroconidia undergo a process spherulation. They enlarge numerous nuclear divisions to form spherical structure, then internally segment until spherule is filled with multiple cells...

ABSTRACT Coccidioides spp. are part of a group thermally dimorphic fungal pathogens, which grow as filamentous cells (hyphae) in the soil and transform to different morphology upon inhalation into host. The host form, spherule, is unique highly undercharacterized due both technical biocontainment challenges. Each spherule arises from an environmental spore (arthroconidium), matures, develops hundreds internal endospores, released rupture. endospore can then go on form another cycle called...

Abstract The human fungal pathogen Histoplasma changes its morphology in response to temperature. At 37°C it grows as a budding yeast whereas at room temperature transitions hyphal growth. Prior work has demonstrated that 15-20% of transcripts are temperature-regulated, and transcription factors Ryp1-4 necessary establish However, little is known about transcriptional regulators the program. To identify TFs regulate filamentation, we utilize chemical inducers We show addition cAMP analogs or...