Vol. 05, 2018

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.

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.

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A Cinderella story: how the vacuolar proteases Pep4 and Prb1 do more than cleaning up the cell’s mass degradation processes

Winnie Kerstens1,2 and Patrick Van Dijck1,2

This review summarizes the expanded roles of the Saccharomyces cerevisiae vacuolar proteases Pep4 and Prb1 in non-vacuolar activities outside of autophagy, such as programmed cell death, protection from harmful protein forms, and gene expression regulation. The potential implications of these findings for fungal biology and drug target discovery, including insights for mammalian cell studies, are highlighted, emphasizing the need for a deeper understanding of these molecular processes.

The biosynthesis of pyoverdines

Michael T. Ringel1 and Thomas Brüser1

This review provides an overview of pyoverdine biosynthesis, emphasizing the distinctive fluorophore shared by various pyoverdines derived from ferribactins and the role of periplasmic processes in the maturation and modification of these siderophores, critical for the growth and colonization of hosts by fluorescent pseudomonads.

The translationally controlled tumor protein TCTP is involved in cell cycle progression and heat stress response in the bloodstream form of Trypanosoma brucei

Borka Jojic1, Simona Amodeo1,2 and Torsten Ochsenreiter1

This study reveals the involvement of the translationally controlled tumor protein TCTP in cell cycle regulation and heat stress response in the bloodstream form of Trypanosoma brucei, shedding light on its role in these cellular processes.

Toxin release mediated by the novel autolysin Cwp19 in Clostridium difficile

Imane El Meouche1 and Johann Peltier2,3

In this article, the authors comment on the study "Cwp19 is a novel lytic transglycosylase involved in stationary-phase autolysis resulting in toxin release in Clostridium difficile" by Wydau-Dematteis (MBio, 2018) that characterizes a novel peptidoglycan hydrolase, Cwp19, in Clostridioides difficile, highlighting its glucose-dependent mediation of toxins secretion and suggesting a potential role in the pathogenesis of this bacterium, contributing to the understanding of these enzymes in C. difficile and their implication in pathogenicity.

Single telomere length analysis in Ustilago maydis, a high-resolution tool for examining fungal telomere length distribution and C-strand 5’-end processing

Ganduri Swapna1, Eun Young Yu1 and Neal F. Lue1, 2

This article introduces the development of single telomere length analysis (STELA) for Ustilago maydis, a basidiomycete fungus, enabling the precise measurement of telomere lengths and distributions. The study demonstrates STELA's utility in revealing the existence of relatively short telomeres in wild-type cells, preferential loss of long telomeres in a mutant defective in telomere replication, and the characterization of telomere C-strand 5’ ends, highlighting U. maydis as a strong model for telomere research.

Escherichia coli hijack Caspr1 receptor to invade cerebral vascular and neuronal hosts

Wei-Dong Zhao1, Dong-Xin Liu1, Yu-Hua Chen1

In this article, the authors comment on the study "Caspr1 is a host receptor for meningitis-causing Escherichia coli" by Zhao et al. (Nat Commun, 2ß18) that identified Caspr1 as a key host receptor for E. coli virulence factor IbeA, facilitating E. coli penetration through the blood-brain barrier (BBB). The research demonstrated that targeting the interaction between IbeA and Caspr1 could potentially neutralize E. coli virulence and prevented meningitis, shedding light on the mechanisms of bacterial invasion into brain endothelial cells and hippocampal neurons.

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A novel basolateral type IV secretion model for the CagA oncoprotein of Helicobacter pylori

Silja Wessler1 and Steffen Backert2

In this article, the authors comment on the study "Helicobacter pylori Employs a Unique Basolateral Type IV Secretion Mechanism for CagA Delivery" by Tegtmeyer et al. (Cell Host Microbe, 2017), discussing that the finding of a T4SS receptor suggests the presence of a sophisticated control mechanism for the injection of CagA and the possible impact of this novel signaling cascade on pathogenesis during infection with Helicobacter pylori.

Microbial wars: competition in ecological niches and within the microbiome

Maria A. Bauer1, Katharina Kainz1, Didac Carmona-Gutierrez1 and Frank Madeo1,2

In this Editorial Bauer et al. provide a brief overview on microbial competition and discuss some of its roles and consequences that directly affect humans.

Exploring the mechanism of amebic trogocytosis: the role of amebic lysosomes

Allissia A. Gilmartin1 and William A. Petri, Jr1,2,3

In this article, the authors comment on the study "Inhibition of Amebic Lysosomal Acidification Blocks Amebic Trogocytosis and Cell Killing" by Gilmartin et al. (MBio, 2017), discussing the the role of amebic lysosomes in Trogocytosis, the intracellular transfer of fragments of cell material.

Evolution of substrate specificity in the Nucleobase-Ascorbate Transporter (NAT) protein family

March 22, 2018

L-ascorbic acid (vitamin C) is an essential metabolite in animals and plants due to its role as an enzyme co-factor and antioxidant activity. Here, Kourkoulou et al. show further evidence that ascorbate-specific Nucleobase-Ascorbate Transporters (NATs) evolved by optimization of a sub-function of ancestral nucleobase transporters.

Helicobacter hepaticus polysaccharide induces an anti-inflammatory response in intestinal macrophages

March 22, 2018

In this article, the authors comment on the study "A Large Polysaccharide Produced by Helicobacter hepaticus Induces an Anti-inflammatory Gene Signature in Macrophages. " by Danne et al, (Cell Host Microbe 2017), discussing the interactions between H. hepaticus and intestinal macrophages that promote mutualism.

Endolysosomal pathway activity protects cells from neurotoxic TDP-43

March 21, 2018

In this article, the authors comment on the study "TDP-43 controls lysosomal pathways thereby determining its own clearance and cytotoxicity" by Leibiger et al. (Hum Mol Genet, 2018), proposing that ameliorating endolysosomal pathway activity enhances cell survival in TDP‑43-associated diseases.

Valine biosynthesis in Saccharomyces cerevisiae is regulated by the mitochondrial branched-chain amino acid aminotransferase Bat1

March 21, 2018

In Saccharomyces cerevisiae, the yeast, the Bat1 and Bat2 proteins, which are branched-chain amino acid aminotransferases, play distinct roles in valine biosynthesis and cell growth regulation, with Bat1 primarily located in the mitochondria and Bat2 in the cytosol, and the mitochondria being identified as the major site of valine biosynthesis in this yeast.

Microbial competition between Escherichia coli and Candida albicans reveals a soluble fungicidal factor

March 7, 2018

Localized and systemic fungal infections caused by Candida albicans can lead to significant mortality and morbidity. Here, Cabral et al. show that E. coli produces a soluble factor that kills C. albicans in a magnesium-dependent fashion such that depletion of available magnesium is essential for toxicity.

Spontaneous mutations in CYC8 and MIG1 suppress the short chronological lifespan of budding yeast lacking SNF1/AMPK

February 19, 2018

Chronologically aging yeast cells are prone to adaptive regrowth, whereby mutants with a survival advantage spontaneously appear and re-enter the cell cycle in stationary phase cultures. Here, Magani et al. identified specific downstream SNF1 targets responsible for CLS extension during CR.

Decreasing cytosolic translation is beneficial to yeast and human Tafazzin-deficient cells

February 18, 2018

Cardiolipin (CL) optimizes diverse mitochondrial processes, including oxidative phosphorylation (OXPHOS). Here, de Taffin de Tilques et al. describe that a diminished capacity of CL remodeling deficient cells to preserve protein homeostasis is likely an important factor contributing to the pathogenesis of Barth Syndrome (BTHS) and identifies cytosolic translation as a potential therapeutic target for the treatment of this disease.

Two distinct penicillin binding proteins promote cell division in different Salmonella lifestyles

February 18, 2018

In this article, the authors comment on the study "A Specialized Peptidoglycan Synthase Promotes Salmonella Cell Division inside Host Cells" by Castanheira et al. (mBio, 2017), discussing insights in two distinct penicillin binding proteins that promote cell division in different Salmonella lifestyles.

Production of poly-β-1,6-N-acetylglucosamine by MatAB is required for hyphal aggregation and hydrophilic surface adhesion by Streptomyces

February 12, 2018

In this article van Dissel et al. describe new insights to allow better control of liquid-culture morphology of streptomycetes, which may be harnessed to improve growth and industrial exploitation of these highly versatile natural product and enzyme producers.

Impact of F1Fo-ATP-synthase dimer assembly factors on mitochondrial function and organismic aging

January 30, 2018

In aerobic organisms, mitochondrial F1Fo-ATP-synthase is the major site of ATP production. Here, Rampello et al. report on the role of the two dimer assembly factors PaATPE and PaATPG of the aging model Podospora anserina validating a model that links mitochondrial membrane remodeling to aging and identify specific molecular components triggering this process.