Commentary, In the pit

Staphylococcus aureus type I signal peptidase: essential or not essential, that’s the question

Wouter L.W. Hazenbos1, Elizabeth Skippington2 and Man-Wah Tan1

This article comments on work published by Morisaki et al. (mBio, 2016), which characterized a novel ABC transporter. This transporter apparently compensates for SpsB’s essential function by mediating alternative cleavage of a subset of proteins at a site distinct from the SpsB-cleavage site, leading to SpsB-independent secretion.

Transceptors as a functional link of transporters and receptors

George Diallinas

A relative newcomer in environment sensing are the so called transceptors, membrane proteins that possess both solute transport and receptor-like signaling activities. Now, the transceptor concept is further enlarged to include micronutrient sensing via the iron and zinc high-affinity transporters of Saccharomyces cerevisiae.

S. pombe placed on the prion map

Jacqueline Hayles

This article comments on work published by Sideri et al. (Microbial Cell, 2017), which identified the Ctr4 prion in S. pombe.

Using microbes as a key tool to unravel the mechanism of autophagy and the functions of the ATG proteins

Mario Mauthe1,2 and Fulvio Reggiori1,2

Microbes have served to discover and characterize unconventional functions of the ATG proteins, which are uncoupled from their role in autophagy. In our recent study, we have taken advantage of viruses as a screening tool to determine the extent of the unconventional functions of the ATG proteome and characterize one of them.

Autophagy: one more Nobel Prize for yeast

Andreas Zimmermann1, Katharina Kainz1, Aleksandra Andryushkova1, Sebastian Hofer1, Frank Madeo1,2 and Didac Carmona-Gutierrez1

The recent announcement of the 2016 Nobel Prize in Physiology or Medicine, awarded to Yoshinori Ohsumifor the discoveries of mechanisms governing autophagy, underscores the importance of intracellular degradation and recycling. Here we provide a quick historical overview that mirrors both the importance of autophagy as a conserved and essential process for cellular life and death as well as the crucial role of yeast in its mechanistic characterization.

Physiology, phylogeny, and LUCA

William F. Martin1,2, Madeline C. Weiss1, Sinje Neukirchen3, Shijulal Nelson-Sathi4, Filipa L. Sousa3

Genomes record their own history. But if we want to look all the way back to life's beginnings some 4 billion years ago, the record of microbial evolution that is preserved in prokaryotic genomes is not easy to read. The classical approach has been to look for genes that are universally distributed. Another approach is to make all trees for all genes, and sift out the trees where signals have been overwritten by lateral gene transfer. What is left ought to be ancient. If we do that, what do we find?

The curious case of vanishing mitochondria

Anna Karnkowska1 and Vladimír Hampl2

Due to their involvement in the energy metabolism, mitochondria are essential for most eukaryotic cells. Microbial eukaryotes living in low oxygen environments possess reduced forms of mitochondria, namely mitochondrion-related organelles (MROs). Recently, the first microbial eukaryote with neither mitochondrion nor MRO was characterized – Monocercomonoides sp. The discovery of such bona fide amitochondriate eukaryote broadens our knowledge about the diversity and plasticity of eukaryotic cells and provides a substantial contribution to our understanding of eukaryotic cell evolution.

Accumulation of metabolic side products might favor the production of ethanol in Pho13 knockout strains

Guido T. Bommer, Francesca Baldin & Emile Van Schaftingen

This article comments on work published by Collard et al. (Nat Chem Biol, 2016), which describes the discovery of a striking example illustrating the metabolite repair concept.

Sexually transmitted infections: old foes on the rise

Didac Carmona-Gutierrez1,*, Katharina Kainz1 and Frank Madeo1,2,*

Sexually transmitted infections (STIs) are commonly spread via sexual contact. It is estimated that one million STIs are acquired every day worldwide. Besides their impact on sexual, reproductive and neonatal health, they can cause disastrous and life-threatening complications if left untreated. In addition to this personal burden, STIs also represent a socioeconomic problem, deriving in treatment costs of tremendous proportions. Despite a substantial progress in diagnosis, treatment and prevention, the incidence of many common STIs is increasing, and STIs continue to represent a global public health problem and a major cause for morbidity and mortality. With this Special Issue, Microbial Cell provides an in-depth overview of the eight major STIs, covering all relevant features of each infection.

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In the beginning was the word: How terminology drives our understanding of endosymbiotic organelles

January 21, 2019

This In the Pit article argues that the naming conventions for biological entities influence research perspectives and methodologies, advocating for mitochondria and plastids to be classified and named as bacteria due to their endosymbiotic origins, with potential implications for our understanding of bacterial prevalence, definitions of the microbiome and multicellularity, and the concept of endosymbiotic domestication.

What’s in a name? How organelles of endosymbiotic origin can be distinguished from endosymbionts

January 21, 2019

This In the Pit article suggests redefining the relationship between hosts and endosymbionts, like mitochondria and plastids, as a single species based on "sexual symbiont integration," the loss of independent speciation, and congruence in genetic recombination and population sizes, rather than solely on historic classifications or structural properties.