Molecular cloning and expression of a cDNA encoding a Coccidioides posadasii 1,2-alpha-mannosidase identified in the coccidioidal T27K vaccine by immunoproteomic methods

Characterization of the Growth and Morphology of a BSL-2 Coccidioides posadasii Strain That Persists in the Parasitic Life Cycle at Ambient CO2

Coccidioides is a dimorphic fungus responsible for Valley Fever and is the cause of severe morbidity and mortality in the infected population. Although there is some insight into the genes, pathways, and growth media involved in the parasitic to saprophytic growth transition, the exact determinants that govern this switch are largely unknown. In this work, we examined the growth and morphology of a Coccidioides posadasii strain (C. posadasii S/E) that efficiently produces spherules and endospores and persists in the parasitic life cycle at ambient CO2. We demonstrated that C. posadasii S/E remains virulent in an insect infection model. Surprisingly, under spherule-inducing conditions, the C. posadasii S/E culture was found to be completely hyphal. Differential interference contrast (DIC) and transmission electron microscopy (TEM) revealed unexpected cellular changes in this strain including cell wall remodeling and formation of septal pores with Woronin bodies. Our study suggests that the C. posadasii S/E strain is a useful BSL-2 model for studying mechanisms underlying the parasitic to saprophytic growth transition—a morphological switch that can impact the pathogenicity of the organism in the host.

Mannoside recognition and degradation by bacteria

Mannosides constitute a vast group of glycans widely distributed in nature. Produced by almost all organisms, these carbohydrates are involved in numerous cellular processes, such as cell structuration, protein maturation and signalling, mediation of protein-protein interactions and cell recognition. The ubiquitous presence of mannosides in the environment means they are a reliable source of carbon and energy for bacteria, which have developed complex strategies to harvest them. This review focuses on the various mannosides that can be found in nature and details their structure. It underlines their involvement in cellular interactions and finally describes the latest discoveries regarding the catalytic machinery and metabolic pathways that bacteria have developed to metabolize them.

Identification, molecular characterization, and expression analysis of a DOMON-like type 9 carbohydrate-binding module domain-containing protein of Coccidioides posadasii

Previously, we investigated the effect of N-acetylglucosamine (GlcNAc) on Coccidioides posadasii chitinolytic enzymes during in vitro spherule-endospore (S/E) phase culture. During those studies, sodium dodecyl sulfatepolyacrylamide gel electrophoresis analysis of supernatants from S/E phase cultures grown in Converse medium with or without added GlcNAc revealed a ∼ 28-kDa band (CFP28), whose abundance was increased by GlcNAc in parallel with the chitinolytic enzymes. Mass spectrometry (MS) of the CFP28 band revealed peptides that matched an open reading frame found in the tentative consensus sequence, TC20325, retrieved from the Dana Farber Cancer Institute C. posadasii Gene Index Database. The TC20325 cDNA sequence was used to design internal primers based on MS peptides and a full-length cDNA was isolated using a combination of rapid amplification of cDNA ends and reverse transcription-polymerase chain reaction. The deduced amino acid sequence of the full-length cDNA consists of 231 amino acid residues with a 19 aa signal peptide. The mature protein has a calculated molecular mass of ∼ 24.5 kDa, a theoretical pI of 6.09, and consists of a single DOMON-like type 9 carbohydrate-binding module (CBM9-like-3) conserved domain. The protein shares the highest sequence similarity (≥57%) to hypothetical proteins from fungi within the Pezizomycotina subphylum of Ascomycota. Antiserum against a recombinant version of CFP28 recognized native CFP28 in S/E phase cells and culture supernatants. CFP28 mRNA and protein expression were detectable in S/E phase in Converse medium, but were increased in the presence of added GlcNAc. Purified native CFP28 reacted with pooled sera from patients with coccidioidomycosis.

Recent advances in our understanding of the environmental, epidemiological, immunological, and clinical dimensions of coccidioidomycosis

Coccidioidomycosis is the endemic mycosis caused by the fungal pathogens Coccidioides immitis and C. posadasii. This review is a summary of the recent advances that have been made in the understanding of this pathogen, including its mycology, genetics, and niche in the environment. Updates on the epidemiology of the organism emphasize that it is a continuing, significant problem in areas of endemicity. For a variety of reasons, the number of reported coccidioidal infections has increased dramatically over the past decade. While continual improvements in the fields of organ transplantation and management of autoimmune disorders and patients with HIV have led to dilemmas with concurrent infection with coccidioidomycosis, they have also led to advances in the understanding of the human immune response to infection. There have been some advances in therapeutics with the increased use of newer azoles. Lastly, there is an overview of the ongoing search for a preventative vaccine.

Fungal cell wall vaccines: an update

This discussion is intended to be an overview of current advances in the development of fungal cell wall vaccines with an emphasis on Candida; it is not a comprehensive historical review of all fungal cell wall vaccines. Selected, more recent, innovative strategies for developing fungal vaccines will be highlighted. Both scientific and logistical obstacles related to the development of, and clinical use of, fungal vaccines will be discussed.