A vitamin-free minimal synthetic medium forCryptococcus neoformans

Abstract

The use of a simple synthetic medium is essential for study on the growth and physiology of Cryptococcus neoformans. In the present study, a minimal synthetic liquid medium (MSM) was tested for the growth of 23 C. neoformans strains. This medium contained a low concentration of glucose, ammonium sulphate and inorganic salts with a pH value of 4.5, but no amino acids or vitamins. The strains were starved for 4 days to eliminate nutrients which might have been carried over from their pre-culture medium. Then, they were inoculated in the MSM as an initial OD of 0.020 at 550 nm and incubated at 37 degrees C for 20 days. Cell growth was generally monitored daily by measuring the absorbance at 550 nm. The medium supported the growth of the strains tested and gave an average final OD of 0.500. The results obtained indicate that C. neoformans may be autotrophic with respect to vitamins and in particular to thiamine. The MSM medium is easy to prepare and store. It is highly reproducible and useful for studies on the growth and physiology of C. neoformans.

Characterization of Thi9, a Novel Thiamine (Vitamin B1) Transporter from Schizosaccharomyces pombe

“…In these organisms, thiamine auxotrophy correlates with a lack of orthologs of THI5 and can be complemented with HMP (25). Thiamine auxotrophic species are more frequent in the genera Rhodutorula and Cryptococcus and include the fatal human pathogen Cryptococcus neoformans (4,60). C. neoformans contains a protein with high similarity to Thi9 from S. pombe ( Fig.…”

Inositol Polyphosphate Kinases, Fungal Virulence and Drug Discovery

“…Even with access to antiretroviral and antifungal therapy, mortality rates due to cryptococcal meningitis remain at 20%–40% [ 35 , 36 , 37 , 38 ]. C. neoformans is also a powerful model for elucidating the mechanisms that fungi use to cause disease: it is a budding yeast that is easy to grow, with minimal nutritional requirements and a defined mating cycle [ 39 , 40 , 41 , 42 ]; it produces a suite of virulence traits that are easily measured; and its haploid genome is highly amenable to targeted gene deletion, which can be combined with mating crosses to increase the number of gene deletions within the same genome [ 43 , 44 ]. Furthermore, a number of vertebrate and invertebrate infection models have been developed to address the impact of gene deletion on pathogenesis and virulence and to assess drug efficacy [ 45 , 46 , 47 , 48 , 49 ], also reviewed in [ 50 , 51 ].…”