Unraveling the Polysaccharide Biosynthesis Potential of Ganoderma lucidum: A Chromosome-Level Assembly Using Hi-C Sequencing

Ganoderma lucidum exhibits the ability to synthesize a diverse range of biologically active molecules with significant pharmaceutical potential, including xylomannan and fucogalactan, which have demonstrated antitumor activity. However, there exists considerable intra-species variability in the capacity to produce these metabolites at high concentrations, likely reflecting the high genomic diversity observed from a limited number of strains sequenced to date. We employed high-throughput shotgun sequencing to obtain the complete genome sequence of G. lucidum strain 5.1, which is distinguished by its remarkable xylomannan synthesis capabilities. Through the utilization of semi-automatic reordering based on conformation capture (Hi-C) data, we substantially enhanced the assembly process, resulting in the generation of 12 chromosome-level scaffolds with a cumulative length of 39 Mbp. By employing both de novo and homology-based approaches, we performed comprehensive annotation of the genome, thereby identifying a diverse repertoire of genes likely involved in polysaccharide biosynthesis. The genome sequence generated in this study serves as a valuable resource for elucidating the molecular mechanisms underlying the medicinal potential of Ganoderma species, discovering novel pharmaceutically valuable compounds, and elucidating the ecological mechanisms of the species. Furthermore, the chromosome contact map obtained for the first time for this species extends our understanding of 3D fungal genomics and provides insights into the functional and structural organization within the fungal kingdom.

Resolution of a fungal mycotic aneurysm after a contaminated steroid injection: a case report

BACKGROUND

In the past ten years there have been three separate outbreaks of fungal contaminated steroid injections from compounding pharmacies. The 2012 outbreak of central nervous system fungal infections associated with contaminated methylprednisolone produced by a United States compounding pharmacy has led to 750 infections (151 with meningitis and paraspinal infections and 325 cases with paraspinal infections without meningitis) and 64 deaths as of October 23, 2013. Exserohilum rostratum has been the predominant pathogen identified by culture, polymerase chain reaction or antibody tests. According to previous reports, cerebral involvement with phaeohyphomycosis has a high risk of morbidity and mortality.

CASE PRESENTATION

We report a 41 year-old Caucasian woman who received a lumbar methylprednisolone injection from a contaminated lot in August 2012. She was diagnosed with fungal meningitis by cerebrospinal fluid pleocytosis and positive (1, 3) beta-D-glucan after cultures and polymerase chain reaction were negative. Two weeks after onset of therapy, she developed a 4.1 mm superior cerebellar artery mycotic aneurysm associated with new stroke symptoms, which resolved with thirty-two weeks of antifungal treatment.

CONCLUSIONS

This is the rare case report of successful medical management of a cerebral mycotic aneurysm with stroke symptoms related to a presumed phaeohyphomycosis in an immunocompetent individual. Further studies are needed to determine the utility of cerebrospinal fluid (1, 3) beta-D-glucan in diagnosing and monitoring patients with meningitis thought to be related to fungal infection.