Cryptococcus spencermartinsiae sp. nov., a basidiomycetous yeast isolated from glacial waters and apple fruits

Seven strains representing a novel yeast species belonging to the genus Cryptococcus were isolated from different substrates from Patagonia Argentina and The Netherlands. Three strains were isolates from a meltwater river draining from the Frias glacier at Mount Tronador situated in Nahuel Huapi National Park (Patagonia) and four were isolated from apple surfaces in Randwijk, The Netherlands. Analysis of the D1/D2 large-subunit and ITS rRNA sequence indicates that these strains represent a single species that is distinct from other species of the Tremellales clade. The name Cryptococcus spencermartinsiae is proposed to accommodate these strains. The type strain is CRUB 1230(T) (= CBS 10760(T)=DVPG 8010(T))

A role for a complex between activated G protein-coupled receptors in yeast cellular mating

Cell-cell fusion is a fundamental process that facilitates a wide variety of biological events in organisms ranging from yeast to humans. However, relatively little is actually understood with respect to fusion mechanisms. In the model organism Saccharomyces cerevisiae, mating of opposite-type cells is triggered by pheromone activation of the G protein-coupled receptors, α-factor receptor (Ste2p) and a-factor receptor (Ste3p), leading to mitogen-activated protein kinase signaling, growth arrest, and cellular fusion events. Herein we now provide evidence of a role for these receptors in the later cell fusion stage of mating. In vitro assays demonstrated the ability of the receptors to promote mixing of proteoliposomes containing phosphatidylserine, potentially based on a pheromone-dependent interaction between Ste2p and Ste3p that was confirmed by tandem affinity purification and cellular pull-down assays. The cellular mating activity of Ste2p was subsequently probed in vivo. Notably, a receptor-null yeast strain expressing N-terminally truncated Ste2p yielded a phenotype demonstrating wild-type signaling but arrested mating. The arrested prezygotes showed evidence of some cell wall erosion but no membrane juxtaposition at the fusion site. Further, in vitro analyses correlated this mutation with loss of the interaction between Ste2p and Ste3p and inhibition of related lipid mixing. Overall, these results support a role for a complex between activated yeast pheromone receptors in later cell fusion stages of mating, possibly mediating events at the level of cell wall digestion and membrane juxtaposition before membrane fusion

Review of adjustable velcro wrap devices for venous ulceration

Compression therapy is the mainstay of treatment for patients with venous leg ulcers. Current gold standard is 4 layer bandaging, which has a significant impact on patients comfort, ability to wear their own shoes, and quality of life, as well as taking significant time to apply, and losing compression over time. This systematic review aims to evaluate the use of Velcro wrap devices for the treatment of venous ulceration. Preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were used to identify articles reporting the use of Velcro wrap devices in patients with venous ulceration. Sixteen articles were identified (14 case series, 1 randomised trial, and 1 audit) reporting on 192 patients. There were reports of improved time to healing, reduced cost by >50%, reduced number and duration of nursing appointments, and improved quality of life in patients in Velcro wrap devices. Although the evidence remains poor, Velcro devices have potential to improve outcomes for patients with venous ulceration and further good quality studies should be undertaken to evaluate these further

Identification of a Cell Death Pathway in Candida albicans during the Response to Pheromone ▿ †

Mating in hemiascomycete yeasts involves the secretion of pheromones that induce sexual differentiation in cells of the opposite mating type. Studies in Saccharomyces cerevisiae have revealed that a subpopulation of cells experiences cell death during exposure to pheromone. In this work, we tested whether the phenomenon of pheromone-induced death (PID) also occurs in the opportunistic pathogen Candida albicans. Mating in C. albicans is uniquely regulated by white-opaque phenotypic switching; both cell types respond to pheromone, but only opaque cells undergo the morphological transition and cell conjugation. We show that approximately 20% of opaque cells, but not white cells, of laboratory strain SC5314 experience pheromone-induced death. Furthermore, analysis of mutant strains revealed that PID was significantly reduced in strains lacking Fig1 or Fus1 transmembrane proteins that are induced during the mating process and, we now show, are necessary for efficient mating in C. albicans. The level of PID was also Ca2+ dependent, as chelation of Ca2+ ions increased cell death to almost 50% of the population. However, in contrast to S. cerevisiae PID, pheromone-induced killing of C. albicans cells was largely independent of signaling via the Ca2+-dependent protein phosphatase calcineurin, even when combined with the loss of Cmk1 and Cmk2 proteins. Finally, we demonstrate that levels of PID vary widely between clinical isolates of C. albicans, with some strains experiencing close to 70% cell death. We discuss these findings in light of the role of prodeath and prosurvival pathways operating in yeast cells undergoing the morphological response to pheromone