Microreviews
A novel c-di-GMP signal system regulates biofilm formation in Pseudomonas aeruginosa
Gukui Chen1 and Haihua Liang1
This article relates to the study "The SiaA/B/C/D signaling network regulates biofilm formation in Pseudomonas aeruginosa" by Chen et al. (EMBO J, 2020) that reveals a novel signaling network encoded by the siaABCD operon in Pseudomonas aeruginosa that regulates biofilm and aggregate formation by controlling the diguanylate cyclase activity of SiaD through phosphorylation-dependent interactions with SiaC, highlighting a potential antimicrobial target.
More than flipping the lid: Cdc50 contributes to echinocandin resistance by regulating calcium homeostasis in Cryptococcus neoformans
Chengjun Cao1 and Chaoyang Xue1,2
In this article, the authors comment on the study "A mechanosensitive channel governs lipid flippase-mediated echinocandin resistance in Cryptococcus neoformans" by Cao et al. (mBio, 2019), which uncovers a dual role for the lipid flippase subunit Cdc50 in Cryptococcus neoformans, linking lipid translocation and calcium signaling via its interaction with the mechanosensitive channel Crm1, thereby contributing to innate resistance against the antifungal drug caspofungin.
New insights in the mode of action of anti-leishmanial drugs by using chemical mutagenesis screens coupled to next-generation sequencing
Arijit Bhattacharya1, Sophia Bigot2, Prasad Kottayil Padmanabhan2, Angana Mukherjee2, Adriano Coelho3, Philippe Leprohon2, Barbara Papadopoulou2 and Marc Ouellette2
In this article, the authors comment on the study "Coupling chemical mutagenesis to next generation sequencing for the identification of drug resistance mutations in Leishmania" by Bhattacharya et al. (Nat Commun, 2019), which introduces Mut-seq, a chemical mutagenesis and sequencing approach, to uncover drug resistance mechanisms in Leishmania, revealing links between lipid metabolism genes and miltefosine resistance, and a protein kinase involved in translation conferring paromomycin resistance.
A holobiont view on thrombosis: unravelling the microbiota’s influence on arterial thrombus growth
Giulia Pontarollo1, Klytaimnistra Kiouptsi1 and Christoph Reinhardt1,2
In this article, the authors comment on the study "The microbiota promotes arterial thrombosis in low-density lipoprotein receptor-deficient mice" by Kiouptsi et al. (mBio, 2019) that showed that commensal microbiota, intricately linked to host physiology, may influence cardiovascular disease, as shown by studies using germ-free atherosclerosis-prone mice to examine how microbial presence and diet affect arterial thrombosis and lesion development.
Tribal warfare: Commensal Neisseria kill pathogen Neisseria gonorrhoeae using its DNA
Magdalene So1 and Maria A. Rendón1
This article comments on work published by Kim et al (Cell Host Microbe, 2019), which adds a new dimension to the concept of commensal protection. It shows that commensal Neisseria kill the closely related pathogen N. gonorrhoeae through an unexpected mechanism, one that involves genetic competence, DNA methylation state and recombination.
Yet another job for the bacterial ribosome
Andrea Origi1,2, Ana Natriashivili1,2, Lara Knüpffer1, Clara Fehrenbach1, Kärt Denks1,2, Rosella Asti1 and Hans-Georg Koch1
This article comments on work published by Knüpffer et al (mBio, 2019), which revealed the intricate interaction of uL23 with yet another essential player in bacteria, the ATPase SecA, which is best known for its role during post-translational secretion of proteins across the bacterial SecYEG translocon
Inhibiting eukaryotic ribosome biogenesis: Mining new tools for basic research and medical applications
Lisa Kofler1, Michael Prattes1 and Helmut Bergler1
This article comments on work published by Awad et al (BMC Biology, 2019), which screened for novel inhibitors of the ribosome biogenesis pathway in yeast.
Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
René Lysdal Bærentsen1, Ditlev Egeskov Brodersen1 and Yong Everett Zhang2
This article comments on work published by Zhang et al (Mol Cell, 2019), which discovered an interesting mode of regulation of purine metabolism unique to Proteobacteria.
Histone deacetylases: revealing the molecular base of dimorphism in pathogenic fungi
November 4, 2015
Fungi, as every living organism, interact with the external world and have to adapt to its fluctuations. For pathogenic fungi, such interaction involves adapting to the hostile environment of their host. Survival depends on the capacity of fungi to detect and respond to external stimuli, which is achieved through a tight and efficient genetic control. Elías-Villalobos et al. propose that histone acetylation is critical to the proper timing and induction of transcription of the genes encoding factors that coordinate changes in morphology with pathogenesis.
Electron microscopy for ultrastructural analysis and protein localization in Saccharomyces cerevisiae
October 12, 2015
The yeast Saccharomyces cerevisiae is a key model system for studying of a multitude of cellular processes because of its amenability to genetics, molecular biology and biochemical procedures. The goal of this review is to guide researchers that want to investigate a particular process at the ultrastructural level in yeast by aiding in the selection of the most appropriate approach to visualize a specific structure or subcellular compartment.
Complex regulation of the sirtuin-dependent reversible lysine acetylation system of Salmonella enterica
October 12, 2015
The extensive involvement of the reversible lysine acylation (RLA) system in metabolism has attracted the attention of investigators interested in understanding the fundamentals of prokaryotic and eukaryotic cell function. Here the authors discuss the implications of recently reported work performed in the enteropathogen Salmonella enterica (mBio (2015) 6(4):e00891-15), which provided the first insights into the integration of the transcriptional regulation of genes encoding the RLA system with the acs gene encoding the central metabolic enzyme acetyl-CoA synthetase (Acs).
A bacterial volatile signal for biofilm formation
September 23, 2015
Bacteria constantly monitor the environment they reside in and respond to potential changes in the environment through a variety of signal sensing and transduction mechanisms in a timely fashion. In their recent study (Chen, et al. mBio (2015), 6: e00392-15), the authors demonstrated that the soil bacterium Bacillus subtilis uses acetic acid as a volatile signal to coordinate the timing of biofilm formation within physically separated cells in the community. They also showed that the bacterium possesses an intertwined gene network to produce, secrete, sense, and respond to acetic acid, in stimulating biofilm formation.
The great escape: Pseudomonas breaks out of the lung
September 23, 2015
The Gram-negative bacterium Pseudomonas aeruginosa is a major cause of hospital-acquired infections and the focus of much attention due to its resistance to many conventional antibiotics. This article discusses the potential mechanisms by which these processes occur as well as the novel techniques used to study ExoS function in vivo.
Peering into the ‘black box’ of pathogen recognition by cellular autophagy systems
August 22, 2015
Autophagy is an intracellular process that plays an important role in protecting eukaryotic cells and maintaining intracellular homeostasis. This review summarises the available evidence regarding the specific recognition of invading pathogens by which they are targeted into host autophagy pathways.
Per aspera ad astra: When harmful chromosomal translocations become a plus value in genetic evolution. Lessons from Saccharomyces cerevisiae
August 20, 2015
This review will focus on chromosomal translocations (either spontaneous or induced) in budding yeast. Indeed, very few organisms tolerate so well aneuploidy like Saccharomyces, allowing in depth studies on chromosomal numerical aberrations. The phenomenon of post-translocational adaptation (PTA) is discussed, providing some new unpublished data and proposing the hypothesis that translocations may drive evolution through adaptive genetic selection.
Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way
August 13, 2015
This article discusses the article "A macrophage subversion factor is shared by intracellular and extracellular pathogens" by Belon et al. (PLoS Pathogens 11(6): e1004969, 2015).
The role of transcriptional ‘futile cycles’ in autophagy and microbial pathogenesis
July 30, 2015
Eukaryotic cells utilize macroautophagy (hereafter autophagy) to recycle cellular materials during nutrient stress. Target of rapamycin (Tor) is a central regulator of this process, acting by post-translational mechanisms, phosphorylating preformed autophagy-related (Atg) proteins to repress autophagy during log-phase growth. A role for this regulatory process in fungal virulence was further demonstrated by showing that overexpression of the Dcp2-associated mRNA-binding protein Vad1 in the AIDS-associated pathogen Cryptococcus neoformans results in constitutive repression of autophagy even under starvation conditions as well as attenuated virulence in a mouse model. In summary, Tor-dependent post-transcriptional regulation of autophagy plays a key role in the facilitation of microbial pathogenesis.
The many facets of homologous recombination at telomeres
July 30, 2015
The ends of linear chromosomes are capped by nucleoprotein structures called telomeres. A dysfunctional telomere may resemble a DNA double-strand break (DSB), which is a severe form of DNA damage. The presence of one DSB is sufficient to drive cell cycle arrest and cell death. Therefore cells have evolved mechanisms to repair DSBs such as homologous recombination (HR). HR-mediated repair of telomeres can lead to genome instability, a hallmark of cancer cells, which is why such repair is normally inhibited. However, some HR-mediated processes are required for proper telomere function. The need for some recombination activities at telomeres but not others necessitates careful and complex regulation, defects in which can lead to catastrophic consequences. Furthermore, some cell types can maintain telomeres via telomerase-independent, recombination-mediated mechanisms. In humans, these mechanisms...