Research Articles

Leishmania guyanensis parasites block the activation of the inflammasome by inhibiting maturation of IL-1β

Mary-Anne Hartley1,¶, Remzi O. Eren1,¶, Matteo Rossi1, Florence Prevel1, Patrik Castiglioni1, Nathalie Isorce1, Chantal Desponds1, Lon-Fye Lye2, Stephen M. Beverley2, Stefan K. Drexler1,&, Nicolas Fasel1,&

The various symptomatic outcomes of cutaneous leishmaniasis relates to the type and potency of its underlying inflammatory responses mediated by Toll-Like-Receptor-3 (TLR3). Here, Hartely et al. investigated other innate pattern recognition receptors capable of reacting to dsRNA and potentially contributing to LRV1-mediated inflammatory pathology. They postulate that avoidance of the inflammasome pathways is likely an important mechanism of virulence in Leishmania infection irrespective of the LRV1-status.

A novel system to monitor mitochondrial translation in yeast

Tamara Suhm1, Lukas Habernig2, Magdalena Rzepka1, Jayasankar Mohanakrishnan Kaimal3, Claes Andréasson3, Sabrina Büttner2,3 and Martin Ott1

In this study Suhm et al. present a novel system to monitor mitochondrial translation by detection of mitochondrial GFP-translation through fluorescence microscopy and flow cytometry in functional mitochondria. This novel tool allows the investigation of the function and regulation of mitochondrial translation during stress signaling, aging and mitochondrial biogenesis.

Fat storage-inducing transmembrane (FIT or FITM) proteins are related to lipid phosphatase/phosphotransferase enzymes

Matthew J Hayes1, Vineet Choudhary2, Namrata Ojha2, John JH Shin3, Gil-Soo Han4, George M. Carman4, Christopher JR Loewen3, William A Prinz2 and Timothy P Levine1

Fat storage-inducing transmembrane (FIT or FITM) proteins have been implicated in the partitioning of triacylglycerol to lipid droplets and the budding of lipid droplets from the ER. Saccharomyces cerevisiae has two FITM homologues and the presented results suggest that Scs3p and Yft2p as well as FITMs in general are lipid phosphatase/phosphotransferase (LPT) enzymes involved in an as yet unknown critical step in phospholipid metabolism.

A versatile plasmid system for reconstitution and analysis of mammalian ubiquitination cascades in yeast

Rossella Avagliano Trezza1,#, Janny van den Burg1, Nico van den Oever1 and Ben Distel1,2

In this article Avagliano Trezza et al. describe a versatile vector system that allows the reconstitution of specific ubiquitination cascades in the model eukaryote Saccharomyces cerevisae (baker’s yeast) that provides a versatile tool to study complex post-translational modifications in a cellular setting.

Alcohols enhance the rate of acetic acid diffusion in S. cerevisiae : biophysical mechanisms and implications for acetic acid tolerance

Lina Lindahl1, Samuel Genheden2, Fábio Faria-Oliveira1, Stefan Allard3, Leif A. Eriksson2, Lisbeth Olsson1, Maurizio Bettiga1,4

Microbial cell factories with the ability to maintain high productivity in the presence of weak organic acids, such as acetic acid, are required in many industrial processes. This study demonstrates that the rate of acetic acid diffusion can be strongly affected by compounds that partition into the cell membrane, and highlights the need for considering interaction effects between compounds in the design of microbial processes.

A genome-wide screen for FTY720-sensitive mutants reveals genes required for ROS homeostasis

Kanako Hagihara1, Kanako Kinoshita1, Kouki Ishida1, Shihomi Hojo1, Yoshinori Kameoka1, Ryosuke Satoh1, Teruaki Takasaki1 and Reiko Sugiura1

Fingolimod hydrochloride (FTY720) is an immune modulator for multiple sclerosis that also induces cancer cell apoptosis through reactive oxygen species generation, with a new study using fission yeast uncovering a gene network related to ROS homeostasis as a possible mechanism of FTY720's toxicity.

Untargeted metabolomics confirms and extends the understanding of the impact of aminoimidazole carboxamide ribotide (AICAR) in the metabolic network of Salmonella enterica

Jannell V. Bazurto1, Stephen P. Dearth2, Eric D. Tague2, Shawn R. Campagna2 and Diana M. Downs1

In Salmonella enterica, aminoimidazole carboxamide ribotide (AICAR) is a purine biosynthetic intermediate and a substrate of the AICAR transformylase/IMP cyclohydrolase (PurH) enzyme. Data herein describe the use of metabolomics to identify the metabolic state of mutant strains and probe the underlying mechanisms used by AICAR to inhibit thiamine synthesis. The results obtained provide a cautionary tale of using metabolite concentrations as the only data to define the physiological state of a bacterial cell.

The cytosolic glyoxalases of Plasmodium falciparum are dispensable during asexual blood-stage development

Cletus A. Wezena1, Romy Alisch1, Alexandra Golzmann2, Linda Liedgens1, Verena Staudacher1,3, Gabriele Pradel2 and Marcel Deponte1,3

In this study the authors demonstrate that, PfGlo1 and PfcGlo2 are dispensable during asexual blood-stage development while the loss of PfcGlo2 may induce the formation of transmissible gametocytes. These combined data show that PfGlo1 and PfcGlo2 are most likely not suited as targets for selective drug development against the malaria parasite Plasmodium falciparum.

Aminoglycoside resistance profile and structural architecture of the aminoglycoside acetyltransferase AAC(6’)-Im

Clyde A. Smith1, Monolekha Bhattacharya2, Marta Toth2, Nichole K. Stewart2 and Sergei B. Vakulenko2

AAC(6')-Im, a monofunctional acetyltransferase, imparts increased resistance to certain aminoglycosides compared to its bifunctional homolog AAC(6')-Ie, with structural studies revealing differences in substrate binding that explain the discrepancies in their enzymatic activity and resistance profiles.

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Two distinct and competitive pathways confer the cellcidal actions of artemisinins

January 1, 2015

The biological actions of artemisinin (ART), an antimalarial drug derived from Artemisia annua, remain poorly understood and controversial. This article concludes that ARTs are endowed with two major and distinct types of properties: a potent and specific mitochondria-dependent reaction and a more general and less specific heme-mediated reaction. The competitive nature of these two actions could be explained by their shared source of the consumable ARTs, so that inhibition of the heme-mediated degradation pathway would enable more ARTs to be available for the mitochondrial action. These properties of ARTs can be used to interpret the divergent antimalarial and anticancer actions of ARTs.

Measurement of apoptosis by SCAN©, a system for counting and analysis of fluorescently labelled nuclei

November 26, 2014

This work reports on a system for analyses of apoptosis-like programmed cell death in fungal hyphae that is composed of several modules, which enable automatic quantification of nuclei with chromatin condensation and DNA strand break in large datasets according to nuclei-associated fluorescent markers.

Rewiring yeast acetate metabolism through MPC1 loss of function leads to mitochondrial damage and decreases chronological lifespan

November 18, 2014

This work shows that MPC1-deficient cells make up for their impairment in mitochondrial pyruvate with a metabolic rewiring which involves several intermediates of the mitochondrially localized TCA cycle and the cytosolic glyoxylate shunt but ultimately results in a pro-aging process.

Overexpression of the transcription factor Yap1 modifies intracellular redox conditions and enhances recombinant protein secretion

October 31, 2014

This article investigates the role of Yap1 during the production of recombinant secretory proteins in glucose based growth conditions in Pichia pastoris, and reports a novel role of Yap1 during ER-resident oxidative protein folding.

Functional analysis of lipid metabolism genes in wine yeasts during alcoholic fermentation at low temperature

October 29, 2014

This study confirms the importance of specific genes in growth and fermentation activity of Saccharomyces cerevisiae at low temperature.

Angiotensin II type 1 receptor blockers increase tolerance of cells to copper and cisplatin

October 24, 2014

This study reports the identification of the drug class of Angiotensin II Type 1 receptor blockers (ARBs) and shows that specific ARBs increase yeast tolerance to Cu and Cp, and affect markers of Cu-induced apoptosis. Likewise, this study finds that specific ARBs increase human cell line tolerance to Cu and decrease the prevalence of apoptotic markers.

An extensive endoplasmic reticulum-localised glycoprotein family in trypanosomatids

October 1, 2014

This work describes a novel family of type I membrane proteins ("invariant glycoproteins") and proposes them as trypanosomatid-specific ER-localised glycoproteins, with potential contributions to life cycle progression and immunity, that utilise oligomerisation as an ER retention mechanism.

Time resolved DNA occupancy dynamics during the respiratory oscillation uncover a global reset point in the yeast growth program

September 1, 2014

Using multiple approaches, this work implies a nucleosome focusing event as a key step that resets transcription during the respiratory oscillation.

Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

August 27, 2014

This work characterizes the involvement of MAPK signaling pathways in cell death induced by acetic acid in Saccharomyces cerevisiae.

Extracellular calcium triggers unique transcriptional programs and modulates staurosporine-induced cell death in Neurospora crassa

August 9, 2014

The results presented here reveal that in Neurospora crassa, extracellular Ca2+ modulates cell death and the transcriptional alterations induced by staurosporine, and lead to the identification of two novel putative Ca2+-binding proteins, encoded by the NCU08524 and NCU06607 genes.

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