A pair of congenic Cryptococcus neoformans var. neoformans strains, B-4476 (a mating type) and B-4500 (a mating type), that presumably differ only in mating type was constructed. This pair and their progeny, five a type and five a type, were tested for virulence in mice. In the parent strains as well as the progeny, a type was clearly more virulent than a type. In addition, death tended to occur earlier among the a-strain-infected mice that died than among the mice that died by infection caused by a strains. These data strongly suggest the genetic association of virulence with mating type in this human fungal pathogen.

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. Previously (Geiser et al. 2013; Phytopathology 103:400-408. 2013), the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani Species Complex (FSSC). Subsequently, this concept was challenged by one research group (Lombard et al. 2015 Studies in Mycology 80: 189-245) who proposed dividing Fusarium into seven genera, including the FSSC as the genus Neocosmospora, with subsequent justification based on claims that the Geiser et al. (2013) concept of Fusarium is polyphyletic (Sandoval-Denis et al. 2018; Persoonia 41:109-129). Here we test this claim, and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species recently described as Neocosmospora were recombined in Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural and practical taxonomic option available.

This article is to alert medical mycologists and infectious disease specialists of recent name changes of medically important species of the filamentous mold Fusarium. Fusarium species can cause localized and life-threating infections in humans. Of the 70 Fusarium species that have been reported to cause infections, close to one-third are members of the Fusarium solani species complex (FSSC), and they collectively account for approximately two-thirds of all reported Fusarium infections. Many of these species were recently given scientific names for the first time by a research group in the Netherlands, but they were misplaced in the genus Neocosmospora. In this paper, we present genetic arguments that strongly support inclusion of the FSSC in Fusarium. There are potentially serious consequences associated with using the name Neocosmospora for Fusarium species because clinicians need to be aware that fusaria are broadly resistant to the spectrum of antifungals that are currently available.

Genetic similarities and differences between type I and type II Candida stellatoidea were 'txied. The electrophoretic karyotype, mitochondrial DNA (mtDNA) restriction patterns, and midrepe ence of nuclear DNA in type I C. stellatoidea were clearly distinguishable from those of a reference cul Of Candida albicans. The karyotype and the major bands of the midrepeat sequence of type II C.s

Seven isolates of Candida stellatoidea were studied for their electrophoretic karyotype, virulence for mice, sensitivity to UV radiation, growth rate in vitro, reaction on cycloheximide-indicator medium, and proteinase activity. The isolates exhibited one of two distinct electrophoretic karyotypes as determined by orthogonal field alternating gel electrophoresis (OFAGE). Four isolates, including the type culture of C. stellatoidea, belonged to electrophoretic karyotype type I by OFAGE, showing eight to nine bands of which at least two bands were less than 1,000 kilobases in gize as estimated by comparison with the DNA bands of Saccharomyces cerevisiae. These isolates failed to produce fatal infection in mice within 20 days when 5 x 105 cells were injected intravenously. The yeasts were cleared from the kidneys of two of three mice tested by day 30. Type I showed proteinase activity on bovine serum albumin agar at pH 3.8 and produced a negative reaction on cycloheximide-bromcresol green medium within 48 h. The three grouped in type II by OFAGE showed banding patterns similar to those of a well-characterized isolate of Candida albicans. The isolates of type II had an electrophoretic karyotype of six to seven bands approximately 1,200 kilobases or greater in siie. All three type II isolates were highly virulent for mice, producing fatality curves similar to those of a previously studied C. albicans isolate. From 80 to 90% of the mice injected with 5 x 105 cells intravenously died within 20 days. The type 1I isolates produced a positive reaction on cycloheximide-bromcresol green agar and showed no proteinase activity on bovine serum albumin agar at the low pH. In addition, the type II isolates grew faster and were significantly more resistant to UV irradiation than the type I isolates. These results indicated that type II, but not type I, isolates can be considered simply as sucrose-negative C. albicans. Candida stellatoidea is presently treated as a synonym for Candida albicans (16). The two yeasts are indistinguishable in morphology of yeast cells, germ tubes, and chlamydospores. The two yeasts share over 90% homology in their total DNA (15) and show similar carbon assimilation spectra except for sucrose. C. albicans assimilates sucrose, whereas the isolates of C. stellatoidea fail to utilize the sugar. They are both diploid organists (8, 23) and contain similar amounts of DNA (8). Molecular genetic studies have shown differences as well as similarities between the two species.