Research, Research Articles

Acetate modulates the inhibitory effect of Lactobacillus gasseri against the pathogenic yeasts Candida albicans and Candida glabrata

Nuno A. Pedro1,2, Gabriela Fontebasso1,2, Sandra N. Pinto1,2, Marta Alves3 and Nuno P. Mira1,2

The results herein described advance the design of new anti-Candida therapies based on probiotics, in particular, those based on vaginal lactobacilli species, helping to reduce the significant burden that infections caused by Candida have today in human health.

D-Serine reduces the expression of the cytopathic genotoxin colibactin

D-Serine reduces the expression of the cytopathic genotoxin colibactin

Jennifer C. Hallam1,#, Sofia Sandalli1,#, Iris Floria1, Natasha C. A. Turner1, Min Tang-Fichaux2, Eric Oswald2,3, Nicky O’Boyle1,4 and Andrew J. Roe1

Sensing and responding to environmental cues and signalling molecules is crucial for bacterial survival. In this study we have identified a D-amino acid that has a strong regulatory effect on the pks genomic island which encodes for biosynthesis genes for the genotoxic compound colibactin.

A modular cloning (MoClo) toolkit for reliable intracellular protein targeting in the yeast Saccharomyces cerevisiae

Pavel Simakin1,#, Christian Koch1,# and Johannes M. Herrmann1

In this study, we describe an advanced Molecular cloning toolkit that is designed for the baker’s yeast Saccharomyces cerevisiae and optimized for the targeting of proteins of interest to specific cellular compartments.

The role of invariant surface glycoprotein 75 in xenobiotic acquisition by African trypanosomes

Alexandr Makarov1, Jakub Began2,†, Ileana Corvo Mautone1,3, Erika Pinto1, Liam Ferguson1, Martin Zoltner1,4, Sebastian Zoll2 and Mark C. Field1,5

By CRISPR/Cas9 knockout and biophysical analysis, we show here that the invariant surface glycoprotein 75 directly binds the the century-old drug suramin and mediates uptake of additional naphthol-related compounds, making this glycoprotein a conduit for entry of at least one structural class of trypanocidal compounds.

The first taxonomic and functional characterization of human CAVD-associated microbiota

Lavinia Curini1,#, Brunilda Alushi2,#, Mary Roxana Christopher3, Simone Baldi1, Leandro Di Gloria4, Pierluigi Stefano5, Anna Laganà5, Luisa Iannone5, Herko Grubitzsch6, Ulf Landmesser7, Matteo Ramazzotti4, Elena Niccolai1,§, Alexander Lauten2,§ and Amedeo Amedei1,8,§

Calcific aortic valve disease (CAVD) is the most common heart valve disorder, defined by a remodeling multistep process. In this study, we aimed to investigate and characterize the presence of valvular microbiota and the associated immune response in human CAV samples originating from two European populations.

Cellular cholesterol licenses <i>Legionella pneumophila</i> intracellular replication in macrophages

Cellular cholesterol licenses Legionella pneumophila intracellular replication in macrophages

Edna Ondari1,#, Ashley Wilkins1,#, Brian Latimer3, Ana-Maria Dragoi2,3 and Stanimir S. Ivanov1

Host membranes are inherently critical for niche homeostasis of vacuolar pathogens such as Legionella. One membrane component that is often subverted by vacuolar bacteria is cholesterol. We provide experimental evidence that cellular cholesterol promotes L. pneumophila replication within a membrane bound organelle in infected macrophages.

DadY (PA5303) is required for fitness of Pseudomonas aeruginosa when growth is dependent on alanine catabolism

Ronnie L. Fulton1 and Diana M. Downs1

Pseudomonas aeruginosa inhabits diverse environmental niches that can have varying nutrient composition. The ubiquity of this organism is facilitated by a metabolic strategy that preferentially utilizes low-energy, non-fermentable organic acids, such as amino acids, rather than the high-energy sugars preferred by many other microbes. The amino acid alanine is among the preferred substrates of P. aeruginosa. The dad locus encodes the constituents of the alanine catabolic pathway of P. aeruginosa. Physiological roles for DadR (AsnC-type transcriptional activator), DadX (alanine racemase), and DadA (D-amino acid dehydrogenase) have been defined in this pathway. An additional protein, PA5303, is encoded in the dad locus in P. aeruginosa. PA5303 is a member of the ubiquitous Rid protein superfamily and is designated DadY based on the data presented herein. (...)

Multiple genome analysis of Candida glabrata clinical isolates renders new insights into genetic diversity and drug resistance determinants

Pedro Pais1,2,3,#, Mónica Galocha1,2,3,#, Azusa Takahashi-Nakaguchi4, Hiroji Chibana4 and Miguel C. Teixeira1,2,3

The emergence of drug resistance significantly hampers the treatment of human infections, including those caused by fungal pathogens such as Candida species. Candida glabrata ranks as the second most common cause of candidiasis worldwide, supported by rapid acquisition of resistance to azole and echinocandin antifungals frequently prompted by single nucleotide polymorphisms (SNPs) in resistance associated genes, such as PDR1 (azole resistance) or FKS1/2 (echinocandin resistance). To determine the frequency of polymorphisms and genome rearrangements as the possible genetic basis of C. glabrata drug resistance, we assessed genomic variation across 94 globally distributed isolates with distinct resistance phenotypes, whose sequence is deposited in GenBank. The(...)

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

December 28, 2017

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.

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.

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.

Mitochondrial energy metabolism is required for lifespan extension by the spastic paraplegia-associated protein spartin

November 30, 2017

This article indicates that spartin, a protein linked to hereditary spastic paraplegias, extends yeast lifespan and reduces age-related damage by associating with mitochondria and interacting with key metabolic proteins, implicating energy metabolism in its protective role during aging.

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

November 27, 2017

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

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.

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

November 9, 2017

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.

Cross-species complementation of bacterial- and eukaryotic-type cardiolipin synthases

November 3, 2017

This article shows that cardiolipin is crucial for cellular respiration and membrane integrity, with cardiolipin synthase enzymes like TbCLS in Trypanosoma brucei being potential drug targets due to their essential role in survival. The study demonstrates TbCLS's ability to restore cardiolipin production in yeast, highlighting the specificity and potential co-localization required for cardiolipin synthesis and remodeling, and underscoring the differences between eukaryotic and prokaryotic cardiolipin synthase mechanisms.

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