Itzhack Polacheck

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A simple new agar medium containing L-canavanine, glycine, and bromthymol blue was found to give a clearer and more accurate distinction between serotype A or D (Cryptococcus neoformans var. neoformans) and serotype B or C (C. neoformans var. gattii) than creatinine-dextrose-bromthymol blue or glycine-cycloheximide-phenol red media. Among 143 isolates of(More)
Phylogenetic analysis of 11 genetic loci and results from many genotyping studies revealed significant genetic diversity with the pathogenic Cryptococcus gattii/Cryptococcus neoformans species complex. Genealogical concordance, coalescence-based, and species tree approaches supported the presence of distinct and concordant lineages within the complex.(More)
In 1999, the population of Vancouver Island, Canada, began to experience an outbreak of a fatal fungal disease caused by a highly virulent lineage of Cryptococcus gattii. This organism has recently spread to the Canadian mainland and Pacific Northwest, but the molecular cause of the outbreak remains unknown. Here we show that the Vancouver Island outbreak(More)
Protoplasts of Cryptococcus neoformans contain phenoloxidase as a membrane-bound enzyme. The enzyme appeared to be attached on the inner side of cytoplasmic membranes. Synthesis of the enzyme was derepressed by low levels of glucose but was not affected by the level of ammonium. Copper chelators which inhibited the phenoloxidase of other organisms did not(More)
Trichosporon asahii (Trichosporon beigelii) infections are rare but have been associated with a wide spectrum of clinical manifestations, ranging from superficial involvement in immunocompetent individuals to severe systemic disease in immunocompromised patients. We report on the recent recovery of T. asahii isolates with reduced susceptibility in vitro to(More)
A double mutant of Cryptococcus neoformans which lacked the ability to produce melanin (Mel-) on media containing diphenols and failed to grow at 37 degrees C (temperature sensitive, Tem-) was obtained by UV irradiation and subsequent cloning. The mutant showed two lesions in melanogenesis in that it lacked the active transport system for diphenolic(More)
Two phenothiazine compounds, trifluoperazine and chlorpromazine, inhibited growth in vitro of the five most common pathogenic yeasts, with MICs ranging from 10 to 40 micrograms/ml. Daily intraperitoneal injections of trifluoperazine (4 to 7 mg/kg of body weight) increased the survival of mice experimentally infected with Candida albicans or Cryptococcus(More)
Over the past two decades, several fungal outbreaks have occurred, including the high-profile 'Vancouver Island' and 'Pacific Northwest' outbreaks, caused by Cryptococcus gattii, which has affected hundreds of otherwise healthy humans and animals. Over the same time period, C. gattii was the cause of several additional case clusters at localities outside of(More)
Candida dubliniensis is a recently discovered yeast species principally associated with carriage and disease in the oral cavities of human immunodeficiency virus (HIV)-infected individuals. To date the majority of isolates of this species have been identified in Europe and North America. In this study, five Candida isolates recovered from separate(More)
New, stable, highly water-soluble, nontoxic polysaccharide conjugates of amphotericin B (AmB) are described. AmB was conjugated by a Schiff-base reaction with oxidized arabinogalactan (AG). AG is a highly branched natural polysaccharide with unusual water solubility (70% in water). A high yield of active AmB was obtained with the conjugates which were(More)