Occidiofungin inhibition of biofilm formation on silicone elastomer surface.

are opportunistic fungal pathogens with medical relevance given their association with superficial to life-threatening infections. An important component of virulence is the ability to form a biofilm. These structures are highly resistant to antifungal therapies and are often the cause of treatment failure.

Inhibition of morphological transition and hyphae extension in Candida spp. by occidiofungin.

Aims: To assess the efficacy of the antifungal, occidiofungin, against Candida albicans and Candida tropicalis morphological transformation.

Methods And Results: Susceptibility assays and morphological data were used to demonstrate that occidiofungin effectively targets C. albicans and C.

Single amino acid mutations in the Saccharomyces cerevisiae rhomboid peptidase, Pcp1p, alter mitochondrial morphology.

Key to mitochondrial activities is the maintenance of mitochondrial morphology, specifically cristae structures formed by the invagination of the inner membrane that are enriched in proteins of the electron transport chain. In Saccharomyces cerevisiae , these cristae folds are a result of the membrane fusion activities of Mgm1p and the membrane-bending properties of adenosine triphosphate (ATP) synthase oligomerization. An additional protein linked to mitochondrial morphology is Pcp1p, a serine protease responsible for the proteolytic processing of Mgm1p.

A Novel Actin Binding Drug with Efficacy.

Occidiofungin is produced by the soil bacterium MS14 and is structurally similar or identical to the burkholdines, xylocandins, and cepacidines. This study identified the primary cellular target of occidiofungin, which was determined to be actin. The modification of occidiofungin with a functional alkyne group enabled affinity purification assays and localization studies in yeast.

Influence of phosphatidylserine and phosphatidylethanolamine on farnesol tolerance in Candida albicans.

Candida albicans is among the most common human fungal pathogens. The ability to undergo the morphological transition from yeast to hyphal growth is critical for its pathogenesis. Farnesol, a precursor in the isoprenoid/sterol pathway, is a quorum-sensing molecule produced by C.

Small RNA Sequencing Based Identification of MiRNAs in Daphnia magna.

Small RNA molecules are short, non-coding RNAs identified for their crucial role in post-transcriptional regulation. A well-studied example includes miRNAs (microRNAs) which have been identified in several model organisms including the freshwater flea and planktonic crustacean Daphnia. A model for epigenetic-based studies with an available genome database, the identification of miRNAs and their potential role in regulating Daphnia gene expression has only recently garnered interest.

Frataxin directly stimulates mitochondrial cysteine desulfurase by exposing substrate-binding sites, and a mutant Fe-S cluster scaffold protein with frataxin-bypassing ability acts similarly.

For iron-sulfur (Fe-S) cluster synthesis in mitochondria, the sulfur is derived from the amino acid cysteine by the cysteine desulfurase activity of Nfs1. The enzyme binds the substrate cysteine in the pyridoxal phosphate-containing site, and a persulfide is formed on the active site cysteine in a manner depending on the accessory protein Isd11. The persulfide is then transferred to the scaffold Isu, where it combines with iron to form the Fe-S cluster intermediate.

Characterization of fungal RTG2 genes in retrograde signaling of Saccharomyces cerevisiae.

Changes in the functional status of mitochondria result in the transcriptional activation of a subset of nuclear-encoded genes in a process referred to as retrograde signaling. In Saccharomyces cerevisiae, this molecular link between mitochondria and the nuclear genome is controlled by three key signaling proteins: Rtg1p, Rtg2p, and Rtg3p. Although the retrograde signaling response has been well characterized in S.

The antifungal occidiofungin triggers an apoptotic mechanism of cell death in yeast.

Occidiofungin is a nonribosomally synthesized cyclic peptide having a base mass of 1200 Da. It is naturally produced by the soil bacterium Burkholderia contaminans MS14 and possesses potent broad-spectrum antifungal properties. The mechanism of action of occidiofungin is unknown.

The senescent rat diaphragm does not exhibit age-related changes in caspase activities, DNA fragmentation, or myonuclear domain.

The diaphragm muscle is essential for normal ventilation and it is chronically active throughout the lifespan. In most skeletal muscles, aging is associated with increased oxidative stress and myofiber atrophy. Since the diaphragm maintains a unique chronic contractile activity, we hypothesized that these alterations would not occur in senescent diaphragms compared to young diaphragms.

Human telomerase acts as a hTR-independent reverse transcriptase in mitochondria.

Human telomerase reverse transcriptase (hTERT) is localized to mitochondria, as well as the nucleus, but details about its biology and function in the organelle remain largely unknown. Here we show, using multiple approaches, that mammalian TERT is mitochondrial, co-purifying with mitochondrial nucleoids and tRNAs. We demonstrate the canonical nuclear RNA [human telomerase RNA (hTR)] is not present in human mitochondria and not required for the mitochondrial effects of telomerase, which nevertheless rely on reverse transcriptase (RT) activity.

The emerging role of telomerase reverse transcriptase in mitochondrial DNA metabolism.

Telomerase is a reverse transcriptase specialized in telomere synthesis. The enzyme is primarily nuclear where it elongates telomeres but recent reports have shown that it also localizes to mitochondria. The function of TERT in mitochondria is largely unknown but the available findings point to a role in mitochondrial DNA metabolism.

Chapter 14 Nucleotide-dependent iron-sulfur cluster biogenesis of endogenous and imported apoproteins in isolated intact mitochondria.

Iron-sulfur [Fe-S] clusters are cofactors of proteins involved in electron transfer, enzyme catalysis, radical generation, sulfur donation, and signal transduction. Biogenesis of [Fe-S] clusters is mediated by numerous conserved proteins present in E. coli and in mitochondria of eukaryotic cells such as yeast and humans.

Internalization of eNOS and NO delivery to subcellular targets determine agonist-induced hyperpermeability.

The molecular mechanisms of endothelial nitric oxide synthase (eNOS) regulation of microvascular permeability remain unresolved. Agonist-induced internalization may have a role in this process. We demonstrate here that internalization of eNOS is required to deliver NO to subcellular locations to increase endothelial monolayer permeability to macromolecules.

GTP is required for iron-sulfur cluster biogenesis in mitochondria.

Iron-sulfur (Fe-S) cluster biogenesis in mitochondria is an essential process and is conserved from yeast to humans. Several proteins with Fe-S cluster cofactors reside in mitochondria, including aconitase [4Fe-4S] and ferredoxin [2Fe-2S]. We found that mitochondria isolated from wild-type yeast contain a pool of apoaconitase and machinery capable of forming new clusters and inserting them into this endogenous apoprotein pool.

Normal human fibroblasts exposed to high- or low-dose ionizing radiation: differential effects on mitochondrial protein import and membrane potential.

How oxidative metabolism modulates effects of ionizing radiation is incompletely understood. Because mitochondria participate in oxidative metabolism, we investigated the modulation of mitochondrial protein import and membrane potential (DeltaPsi) in irradiated cells. Our data show that effects at low dose cannot be predicted from effects at high dose.

GTP in the mitochondrial matrix plays a crucial role in organellar iron homoeostasis.

Mitochondria are the major site of cellular iron utilization for the synthesis of essential cofactors such as iron-sulfur clusters and haem. In the present study, we provide evidence that GTP in the mitochondrial matrix is involved in organellar iron homoeostasis. A mutant of yeast Saccharomyces cerevisiae lacking the mitochondrial GTP/GDP carrier protein (Ggc1p) exhibits decreased levels of matrix GTP and increased levels of matrix GDP [Vozza, Blanco, Palmieri and Palmieri (2004) J.

A GTP:AMP phosphotransferase, Adk2p, in Saccharomyces cerevisiae. Role of the C terminus in protein folding/stabilization, thermal tolerance, and enzymatic activity.

Adenylate kinases participate in maintaining the homeostasis of cellular nucleotides. Depending on the yeast strains, the GTP:AMP phosphotransferase is encoded by the nuclear gene ADK2 with or without a single base pair deletion/insertion near the 3' end of the open reading frame, and the corresponding protein exists as either Adk2p (short) or Adk2p (long) in the mitochondrial matrix. These two forms are identical except that the three C-terminal residues of Adk2p (short) are changed in Adk2p (long), and the latter contains an additional nine amino acids at the C terminus of the protein.

A novel role of Mgm1p, a dynamin-related GTPase, in ATP synthase assembly and cristae formation/maintenance.

In Saccharomyces cerevisiae, two mitochondrial inner-membrane proteins play critical roles in organellar morphology. One is a dynamin-related GTPase, Mgm1p, which participates in mitochondrial fusion. Another is Tim11p, which is required for oligomeric assembly of F1Fo-ATP synthase, which generates ATP through oxidative phosphorylation.

Bimodal targeting of microsomal CYP2E1 to mitochondria through activation of an N-terminal chimeric signal by cAMP-mediated phosphorylation.

Cytochrome P450 2E1 (CYP2E1) plays an important role in alcohol-induced toxicity and oxidative stress. Recently, we showed that this predominantly microsomal protein is also localized in rat hepatic mitochondria. In this report, we show that the N-terminal 30 amino acids of CYP2E1 contain a chimeric signal for bimodal targeting of the apoprotein to endoplasmic reticulum (ER) and mitochondria.