Vol. 05, 2018

Conventional and emerging roles of the energy sensor Snf1/AMPK in Saccharomyces cerevisiae

Paola Coccetti1,2, Raffaele Nicastro1,3 and Farida Tripodi1,2

This review consolidates current knowledge on the conventional and non-conventional functions of the effector kinase Snf1 in yeast, shedding light on its diverse roles in cellular physiology and energy homeostasis.

An unexpected benefit from E. coli: how enterobactin benefits host health

Aileen K. Sewell1,2, Min Han1,2 and Bin Qi1,2

In this article, the authors comment on the study "Microbial Siderophore Enterobactin Promotes Mitochondrial Iron Uptake and Development of the Host via Interaction with ATP Synthase" by Qi et al. (Cell, 2018) that uncovered a surprising role for the Escherichia coli-produced siderophore enterobactin (Ent) in facilitating iron uptake by the host, marking a major shift in the understanding of its function and indicating potential new benefits from commensal bacteria in aiding the host's iron homeostasis.

Protective roles of ginseng against bacterial infection

Ye-Ram Kim1 and Chul-Su Yang1

This review highlights the antibacterial effects of ginseng against pathogenic bacterial infections, discussing its regulation of pathogenic factors and proposing the therapeutic potential of ginseng as a natural antibacterial drug to address antibiotic resistance and toxicity in the context of global public health challenges.

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

Anezia Kourkoulou1,#, Alexandros A. Pittis2,# and George Diallinas1

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

Camille Danne1 and Fiona Powrie1

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

Christine Leibiger1,#, Jana Deisel1,#, Andreas Aufschnaiter2, Stefanie Ambros1, Maria Tereshchenko1, Bert M. Verheijen3,4, Sabrina Büttner2,5, and Ralf J. Braun1

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

Natthaporn Takpho1, Daisuke Watanabe1 and Hiroshi Takagi1

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

Damien J. Cabral1, Swathi Penumutchu1, Colby Norris1,2, Jose Ruben Morones-Ramirez3,4 and Peter Belenky1

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

Nazif Maqani1,#, Ryan D. Fine1,#, Mehreen Shahid1, Mingguang Li1,2, Elisa Enriquez-Hesles1 and Jeffrey S. Smith1

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.

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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.

The logics of metabolic regulation in bacteria challenges biosensor-based metabolic engineering

December 11, 2017

In this article, the authors comment on the study "Molecular and Physiological Logics of the Pyruvate-Induced Response of a Novel Transporter in Bacillus subtilis" by Charbonnier et al. (mBio, 2017), which identified and characterized a pyruvate transport system in the Gram-positive (G+ve) bacterium Bacillus subtilis, a well-established biotechnological workhorse for the production of enzymes, fine chemicals and antibiotics.

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

December 9, 2017

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.

Yeast quiescence exit swiftness is influenced by cell volume and chronological age

December 6, 2017

Quiescence exit swiftness is crucial not only for micro-organisms in competition for an environmental niche, such as yeast, but also for the maintenance of tissue homeostasis in multicellular species. Here, Laporte et al. explore the effect of replicative and chronological age on Saccharomyces cerevisiae quiescence exit efficiency. Overall, their data illustrate that the quiescent state is a continuum evolving with time, early and deep quiescence being distinguishable by the cell’s proficiency to re-enter the proliferation cycle.

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

December 6, 2017

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.

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

December 5, 2017

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

December 1, 2017

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

November 22, 2017

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

November 20, 2017

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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