Killer behavior within the Candida parapsilosis complex

Abstract

A group of 29 isolates of Candida parapsilosis sensu stricto, 29 of Candida orthopsilosis, and 4 of Candida metapsilosis were assayed for the presence of killer activity using Saccharomyces cerevisiae ATCC 26609 as a sensitive strain. All C. metapsilosis isolates showed killer activity at 25 °C while strains of C. parapsilosis sensu stricto or C. orthopsilosis did not exhibit this activity. Sensitivity to killer toxins was evaluated using a set of previously reported killer strains of clinical origin. Only 11 isolates of the C. parapsilosis complex were inhibited by at least one killer isolate without resulting in any clear pattern, except for C. parapsilosis sensu stricto ATCC 22019, which was inhibited by every killer strain with the exception of C. parapsilosis and Candida utilis. The lack of sensitivity to killer activity among isolates of the genus Candida suggests that their toxins belong to the same killer type. Differentiation of species within the C. parapsilosis complex using the killer system may be feasible if a more taxonomically diverse panel of killer strains is employed.

Effect of Bacterial and Yeast Starters on the Formation of Volatile and Organic Acid Compounds in Coffee Beans and Selection of Flavors Markers Precursors During Wet Fermentation

“…The employed yeast strains have been previously inoculated and monitored by Silva et al (2013), Evangelista et al (2014a), Martinez et al (2017), and Bressani et al (2018). Candida parapsilosis is one of the fungi most frequently isolated from human hands, is considered a killer yeast and fungal antagonist based on its ability to produce chemicals that exert cytotoxic effects on the cells of other organisms (Robledo-Leal et al, 2014). Candida species are also reported to lyse Ca2+-pectate.…”

Kinetic modelling and optimisation of antimicrobial compound production byCandida pyralidaeKU736785 for control ofCandida guilliermondii

“…Therefore, in order to achieve better optimisation, mathematical modelling using RSM has been proven to be the method that yields successful optimisation process designs. The process of antimicrobial production can be seen as induced, stimulated by fermentation parameters such as substrate requirements, pH and temperature that are required for cellular growth and product formation (Nwabueze, 2010; Robledo-Leal et al., 2014; Stanbury et al., 1995). These parameters can then be used for optimisation using RSM depending on the characteristics of a specific microorganism being used and can also assist in the design including modelling of the antimicrobial compound production system.…”

MTL genotypes, phenotypic switching, and susceptibility profiles of Candida parapsilosis species group compared to Lodderomyces elongisporus

“…elongisporus strains was assayed by mixing each isolate with YEPD-MB agar [0.3% yeast extract, 0.3% malt extract, 0.5% peptone, 2% glucose, 2% agar, and 0.003% methylene blue (MB); adjusted to pH 4.5 with 0.1 M citrate-phosphate buffer] to a final concentration of 10 6 cells/mL and by streaking the known killer and sensitive isolates on the surface of plates. The plates were incubated at 26°C for up to 72 h. The sensitivity test was considered positive if killer strains showed a clear inhibition zone surrounded by a blue halo [ 39 ]. RNA extraction was performed using TRIzol reagent (Thermo Fisher Scientific, Waltham, MA) according to a protocol provided by the manufacturer.…”