31 research outputs found
Production of carcinogenic acetaldehyde by Candida albicans from patients with potentially malignant oral mucosal disorders
OBJECTIVES: Production of carcinogenic acetaldehyde
by Candida has been suggested to contribute to epithelial
dysplasia and oral carcinogenesis. Oral lichen planus
(OLP), oral lichenoid lesion (OLL) and oral leukoplakia
(OL) are potentially carcinogenic oral diseases where
colonisation by Candida is common, but acetaldehyde
production by Candida has not been studied.
STUDY DESIGN: Acetaldehyde production in ethanol
(11 mM), glucose (100 mM), ethanol–glucose (11 mM
and 100 mM) or red wine (1200 mM ethanol) incubation
by Candida albicans from patients with OLL (n = 6), OLP
(n = 16), OL (n = 6) and controls (n = 6) was measured
by gas chromatography. Participants completed a questionnaire
regarding their smoking habits and alcohol
consumption.
RESULTS: All Candida albicans isolates produced potentially
carcinogenic levels of acetaldehyde (>100 lM) in all
incubations containing ethanol. The control group isolates
produced the highest acetaldehyde levels. Isolates
from smokers produced more acetaldehyde in all incubations
than those from non-smokers. The difference was
significant in ethanol–glucose incubation. Isolates from
patients who were both smokers and drinkers produced
the highest amounts when incubated in ethanol, ethanol–
glucose and wine.
CONCLUSIONS: Candida albicans isolated from potentially
carcinogenic oral diseases can produce mutagenic
amounts of acetaldehyde. Cigarette smoking and alcohol
consumption may favour adaptational changes resulting
in the upregulation of candidal acetaldehyde metabolism.peer-reviewe
Analysis of Synthetic Lethality Reveals Genetic Interactions Between the GTPase Snu114p and snRNAs in the Catalytic Core of the Saccharomyces cerevisiae Spliceosome
Conformational changes of snRNAs in the spliceosome required for pre-mRNA splicing are regulated by eight ATPases and one GTPase Snu114p. The Snu114p guanine state regulates U4/U6 unwinding during spliceosome activation and U2/U6 unwinding during spliceosome disassembly through the ATPase Brr2p. We investigated 618 genetic interactions to identify an extensive genetic interaction network between SNU114 and snRNAs. Snu114p G domain alleles were exacerbated by mutations that stabilize U4/U6 base pairing. G domain alleles were made worse by U2 and U6 mutations that stabilize or destabilize U2/U6 base pairing in helix I. Compensatory mutations that restored U2/U6 base pairing in helix I relieved synthetic lethality. Snu114p G domain alleles were also worsened by mutations in U6 predicted to increase 5′ splice site base pairing. Both N-terminal and G domain alleles were exacerbated by U5 loop 1 mutations at positions involved in aligning exons while C-terminus alleles were synthetically lethal with U5 internal loop 1 mutations. This suggests a spatial orientation for Snu114p with U5. We propose that the RNA base pairing state is directly or indirectly sensed by the Snu114p G domain allowing the Snu114p C-terminal domain to regulate Brr2p or other proteins to bring about RNA/RNA rearrangements required for splicing