Effects of various metal and drug agents on excretion of enzyme aspartyl proteinase in Candida albicans and its role in human physiological processes

ABSTRACT Calcineurin is a conserved Ca2+-calmodulin-activated, serine/threonine-specific protein phosphatase that regulates a variety of physiological processes, e.g., cell cycle progression, polarized growth, and adaptation to salt and alkaline pH stresses. In the pathogenic yeast Cryptococcus neoformans, calcineurin is also essential for growth at 37°C and virulence. To investigate whether calcineurin plays a role in the virulence of Candida albicans, the major fungal pathogen of humans, we constructed C. albicans mutants in which both alleles of the CMP1 gene, encoding the calcineurin catalytic subunit, were deleted. The C. albicans Δcmp1 mutants displayed hypersensitivity to elevated Na+, Li+, and Mn2+ concentrations and to alkaline pH, phenotypes that have been described after calcineurin inactivation in the related yeast Saccharomyces cerevisiae. Unlike S. cerevisiae calcineurin mutants, which exhibit reduced susceptibility to high Ca2+ concentrations, growth of C. albicans was inhibited in the presence of 300 mM CaCl2 after the deletion of CMP1, demonstrating that there are also differences in calcineurin-mediated cellular responses between these two yeast species. In contrast to C. neoformans, inactivation of calcineurin did not cause temperature sensitivity in C. albicans. In addition, hyphal growth, an important virulence attribute of C. albicans, was not impaired in the Δcmp1 mutants under a variety of inducing conditions. Nevertheless, the virulence of the mutants was strongly attenuated in a mouse model of systemic candidiasis, demonstrating that calcineurin signaling is essential for virulence in C. albicans.

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Candida albicans Morphology-Dependent Host FGF-2 Response as a Potential Therapeutic Target

Journal of Fungi ◽

10.3390/jof5010022 ◽

2019 ◽

Vol 5 (1) ◽

pp. 22 ◽

Cited By ~ 3

Author(s):

Sandeep Vellanki ◽

Eun Huh ◽

Stephen Saville ◽

Soo Lee

Keyword(s):

Candida Albicans ◽

Growth Factor ◽

Underlying Mechanism ◽

Yeast Cells ◽

In Vivo Studies ◽

Infection Model ◽

Physiological Processes ◽

Microbial Infections

Angiogenesis mediated by proteins such as Fibroblast Growth Factor-2 (FGF-2) is a vital component of normal physiological processes and has also been implicated in contributing to the disease state associated with various microbial infections. Previous studies by our group and others have shown that Candida albicans, a common agent of candidiasis, induces FGF-2 secretion in vitro and angiogenesis in brains and kidneys during systemic infections. However, the underlying mechanism(s) via which the fungus increases FGF-2 production and the role(s) that FGF-2/angiogenesis plays in C. albicans disease remain unknown. Here we show, for the first time, that C. albicans hyphae (and not yeast cells) increase the FGF-2 response in human endothelial cells. Moreover, Candidalysin, a toxin secreted exclusively by C. albicans in the hyphal state, is required to induce this response. Our in vivo studies show that in the systemic C. albicans infection model, mice treated with FGF-2 exhibit significantly higher mortality rates when compared to untreated mice not given the angiogenic growth factor. Even treatment with fluconazole could not fully rescue infected animals that were administered FGF-2. Our data suggest that the increase of FGF-2 production/angiogenesis induced by Candidalysin contributes to the pathogenicity of C. albicans.

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Candida albicans Morphology Dependent Host FGF-2 Response as a Potential Therapeutic Target

10.20944/preprints201902.0025.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Sandeep Vellanki ◽

Eun Young Huh ◽

Stephen P. Saville ◽

Soo Chan Lee

Keyword(s):

Candida Albicans ◽

Growth Factor ◽

Underlying Mechanism ◽

Yeast Cells ◽

In Vivo Studies ◽

Infection Model ◽

Physiological Processes ◽

Microbial Infections

Angiogenesis mediated by proteins such as Fibroblast Growth Factor – 2 (FGF-2) is a vital component of normal physiological processes and has also been implicated in contributing to disease state associated with various microbial infections. Previous studies by our group and others have shown that Candida albicans, a common agent of candidiasis, induces FGF-2 expression in vitro, and angiogenesis in brains and kidneys during systemic infections. However, the underlying mechanism(s) via which the fungus increases FGF-2 expression and the role(s) that FGF-2/angiogenesis plays in C. albicans disease remain unknown. Here we show, for the first time, that C. albicans hyphae (and not yeast cells) increase the FGF-2 response in human endothelial cells. Moreover, candidalysin, a toxin secreted exclusively by C. albicans in the hyphal state is required to induce this response. Our in vivo studies show that, in the systemic C. albicans infection model, mice treated with FGF-2 exhibit significantly higher mortality rates when compared to untreated mice not given the angiogenic growth factor. Even treatment with fluconazole could not fully rescue infected animals that were administered FGF-2. Our data suggest that the increase of FGF-2 production/angiogenesis induced by candidalysin contributes to the pathogenicity of C. albicans.

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Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094401 ◽

1972 ◽

Vol 30 ◽

pp. 230-231

Author(s):

James Cronshaw ◽

Jamison E. Gilder

Keyword(s):

Plasma Membrane ◽

Atpase Activity ◽

Adenosine Triphosphatase ◽

Higher Plants ◽

High Surface ◽

Root Tip ◽

Animal Cells ◽

Physiological Processes ◽

Tip Cells ◽

Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

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A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119880 ◽

1985 ◽

Vol 43 ◽

pp. 638-639

Author(s):

A. E. Hotchkiss ◽

A. T. Hotchkiss ◽

R. P. Apkarian

Keyword(s):

Green Algae ◽

Vascular Plants ◽

Vascular System ◽

Higher Plants ◽

Wall Structure ◽

Electron Microscopic ◽

Physiological Processes ◽

Scanning Electron Microscopic Study ◽

Scanning Electron Microscopic ◽

Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

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