Changes in cell morphology and carnitine acetyltransferase activity in Candida albicans following growth on lipids and serum and after in vivo incubation in mice

Abstract

Candida aibicans C316, maintained in the yeast form, showed a proliferation of peroxisomes when grown on triolein or serum as sole carbon source but these structures were absent from glucose-grown cells. Peroxisomes were also apparent in C. aibicans obtained after injection into mice and recovery from intraperitoneal washings and kidneys; they may therefore be useful markers to assess a potential in vivo response in cells that are growing in vitro. Transcell-wall structures also occurred in C. aibicans grown on triolein or serum, and in cells cultured in wiwo, but were not seen in cells grown on glucose. These structures consisted of electron-dense f ibrillar material penetrating through the cell wall from the plasmalemma side and protruded out to the exterior of the cell. Endoplasmic reticulum, located at the periphery of the cell, was found to be in close proximity with these cell wall structures. Carnitine acetyltransferase (CAT; EC 2.3.1.7), the key enzyme for the translocation of acetyl units between intracellular compartments, was present in low activities in glucose-grown cells; its activity was increased some 100-fold in trioleingrown cells but only b o l d in serum-grown cells. It was not possible to assess this activity in the in wivo-cultured cells. Two separate CAT proteins, partially purifed from isolated microchondria and peroxisomes, respectively, were identified, with different specificities and kinetic properties.

Candida albicans CTN gene family is induced during macrophage infection: homology, disruption and phenotypic analysis of CTN3 gene

“…We showed that glucose is a potent repressor of gene expression whereas other nonfermentable carbon sources, such as oleate and serum, are inducers of the gene. This pattern of regulation is consistent with the previous finding that peroxisome proliferation is related to growth on lipids or serum as well as during in vivo infection (Sheridan and Ratledge, 1996). Furthermore, under glucose growth conditions, there are only few peroxisomes due to catabolite repression (van der Klei and Veenhuis, 1997) whereas in ethanol, methanol, and oleate, microbodies are more readily detectable (Kunze et al, 2002).…”

Genes involved in β‐oxidation, energy metabolism and glyoxylate cycle are induced by Candida albicans during macrophage infection

“…Moreover, induction of these genes reflects the nutrient deprivation state inside the macrophage and supports the hypothesis that lipid availability may be an alternative option for the pathogen to adapt to glucose starvation (Lorenz and Fink, 2001). Interestingly, it has been observed that peroxisome proliferation is nutrient-dependent and also occurs in C. albicans when it infects mice (Sheridan and Ratledge, 1996). Thus, induction of fungal genes encoding peroxisomal proteins suggests a key role for this organelle during the process of infection.…”

Secreted lipases of Candida albicans : cloning, characterisation and expression analysis of a new gene family with at least ten members

“…The esterase is not able to hydrolyse triolein, tripalmitin and α-lecithin and is therefore defined as a monoester hydrolase. Sheridan et al (1996) have observed that C. albicans is able to grow in media with triolein as a sole source of carbon, suggesting that other lipolytic enzymes must exist. One of these proteins is the gene product of LIP1 (Fu et al 1997).…”