Functional determinants of a small protein controlling a broadly conserved bacterial sensor kinase.

The PhoQ/PhoP two-component system plays a vital role in the regulation of Mg homeostasis, resistance to acid and hyperosmotic stress, cationic antimicrobial peptides, and virulence in , Salmonella and related bacteria. Previous studies have shown that MgrB, a 47 amino acid membrane protein that is part of the PhoQ/PhoP regulon, inhibits the histidine kinase PhoQ. MgrB is part of a negative feedback loop modulating this two-component system that prevents hyperactivation of PhoQ and may also provide an entry point for additional input signals for the PhoQ/PhoP pathway.

The protein architecture of the endocytic coat analyzed by FRET microscopy.

Endocytosis is a fundamental cellular trafficking pathway, which requires an organized assembly of the multiprotein endocytic coat to pull the plasma membrane into the cell. Although the protein composition of the endocytic coat is known, its functional architecture is not well understood. Here, we determine the nanoscale organization of the endocytic coat by FRET microscopy in yeast Saccharomyces cerevisiae.

gammaBOriS: Identification and Taxonomic Classification of Origins of Replication in Gammaproteobacteria using Motif-based Machine Learning.

The biology of bacterial cells is, in general, based on information encoded on circular chromosomes. Regulation of chromosome replication is an essential process that mostly takes place at the origin of replication (oriC), a locus unique per chromosome. Identification of high numbers of oriC is a prerequisite for systematic studies that could lead to insights into oriC functioning as well as the identification of novel drug targets for antibiotic development.

Understanding Substrate Selectivity of Phoslactomycin Polyketide Synthase by Using Reconstituted in Vitro Systems.

Polyketide synthases (PKSs) use simple extender units to synthesize complex natural products. A fundamental question is how different extender units are site-specifically incorporated into the growing polyketide. Here we established phoslactomycin (Pn) PKS, which incorporates malonyl- and ethylmalonyl-CoA, as an in vitro model to study substrate specificity.

Flagellum-Mediated Mechanosensing and RflP Control Motility State of Pathogenic Escherichia coli.

Bacterial flagellar motility plays an important role in many processes that occur at surfaces or in hydrogels, including adhesion, biofilm formation, and bacterium-host interactions. Consequently, expression of flagellar genes, as well as genes involved in biofilm formation and virulence, can be regulated by the surface contact. In a few bacterial species, flagella themselves are known to serve as mechanosensors, where an increased load on flagella experienced during surface contact or swimming in viscous media controls gene expression.

Anthoceros genomes illuminate the origin of land plants and the unique biology of hornworts.

Hornworts comprise a bryophyte lineage that diverged from other extant land plants >400 million years ago and bears unique biological features, including a distinct sporophyte architecture, cyanobacterial symbiosis and a pyrenoid-based carbon-concentrating mechanism (CCM). Here, we provide three high-quality genomes of Anthoceros hornworts. Phylogenomic analyses place hornworts as a sister clade to liverworts plus mosses with high support.

Ratiometric population sensing by a pump-probe signaling system in Bacillus subtilis.

Communication by means of diffusible signaling molecules facilitates higher-level organization of cellular populations. Gram-positive bacteria frequently use signaling peptides, which are either detected at the cell surface or 'probed' by intracellular receptors after being pumped into the cytoplasm. While the former type is used to monitor cell density, the functions of pump-probe networks are less clear.

Characterisation of evolutionarily conserved key players affecting eukaryotic flagellar motility and fertility using a moss model.

Defects in flagella/cilia are often associated with infertility and disease. Motile male gametes (sperm cells) are an ancestral eukaryotic trait that has been lost in several lineages like flowering plants. Here, we made use of a phenotypic male fertility difference between two moss (Physcomitrella patens) ecotypes to explore spermatozoid function.

Transcriptional regulation by σ factor phosphorylation in bacteria.

A major form of transcriptional regulation in bacteria occurs through the exchange of the primary σ factor of RNA polymerase (RNAP) with an alternative extracytoplasmic function (ECF) σ factor. ECF σ factors are generally intrinsically active and are retained in an inactive state via the sequestration into σ factor-anti-σ factor complexes until their action is warranted. Here, we report a previously uncharacterized mechanism of transcriptional regulation that relies on intrinsically inactive ECF σ factors, the activation of which and interaction with the β'-subunit of RNAP depends on σ factor phosphorylation.

DEK1 displays a strong subcellular polarity during Physcomitrella patens 3D growth.

Defective Kernel 1 (DEK1) is genetically at the nexus of the 3D morphogenesis of land plants. We aimed to localize DEK1 in the moss Physcomitrella patens to decipher its function during this process. To detect DEK1 in vivo, we inserted the tdTomato fluorophore into PpDEK1 gene locus.

Growth-rate dependent resource investment in bacterial motile behavior quantitatively follows potential benefit of chemotaxis.

Microorganisms possess diverse mechanisms to regulate investment into individual cellular processes according to their environment. How these regulatory strategies reflect the inherent trade-off between the benefit and cost of resource investment remains largely unknown, particularly for many cellular functions that are not immediately related to growth. Here, we investigate regulation of motility and chemotaxis, one of the most complex and costly bacterial behaviors, as a function of bacterial growth rate.

Chemotaxis and cyclic-di-GMP signalling control surface attachment of Escherichia coli.

Attachment to surfaces is an important early step during bacterial infection and during formation of submerged biofilms. Although flagella-mediated motility is known to be important for attachment of Escherichia coli and other bacteria, implications of motility regulation by cellular signalling remain to be understood. Here, we show that motility largely promotes attachment of E.

Escherichia coli in Auto(trophic) Mode.

It is challenging to convert a heterotrophic organism that loves sugars and other multicarbon compounds as energy and carbon sources into an autotroph that builds all biomass from carbon dioxide. In this issue, Gleizer et al. demonstrate how this can be achieved.

PEATmoss (Physcomitrella Expression Atlas Tool): a unified gene expression atlas for the model plant Physcomitrella patens.

Physcomitrella patens is a bryophyte model plant that is often used to study plant evolution and development. Its resources are of great importance for comparative genomics and evo-devo approaches. However, expression data from Physcomitrella patens were so far generated using different gene annotation versions and three different platforms: CombiMatrix and NimbleGen expression microarrays and RNA sequencing.

Structural organization of biocatalytic systems: the next dimension of synthetic metabolism.

In natural metabolic networks, more than 2000 different biochemical reactions are operated and spatially and temporally co-ordinated in a reaction volume of <1 µm3. A similar level of control and precision has not been achieved in chemical synthesis, so far. Recently, synthetic biology succeeded in reconstructing complex synthetic in vitro metabolic networks (SIVMNs) from individual proteins in a defined fashion bottom-up.

FRET Microscopy in Yeast.

Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts and , two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules.

Red/Far-Red Light Switchable Cargo Attachment and Release in Bacteria-Driven Microswimmers.

In bacteria-driven microswimmers, i.e., bacteriabots, artificial cargos are attached to flagellated chemotactic bacteria for active delivery with potential applications in biomedical technology.

Draft Genome Sequence of Kytococcus schroeteri Strain H01, Isolated from Human Skin.

strain H01 was isolated from the skin of a healthy volunteer who underwent erythromycin treatment for a skin disorder 1 year prior. The draft genome consists of 2.38 Mb, a G+C content of 73.

Quorum Sensing and Metabolic State of the Host Control Lysogeny-Lysis Switch of Bacteriophage T1.

Bacterial viruses, or bacteriophages, are highly abundant in the biosphere and have a major impact on microbial populations. Many examples of phage interactions with their hosts, including establishment of dormant lysogenic and active lytic states, have been characterized at the level of the individual cell. However, much less is known about the dependence of these interactions on host metabolism and signal exchange within bacterial communities.

Reconstitution and Coupling of DNA Replication and Segregation in a Biomimetic System.

A biomimetic system capable of replication and segregation of genetic material constitutes an essential component for the future design of a minimal synthetic cell. Here we have used the simple T7 bacteriophage system and the plasmid-derived ParMRC system to establish in vitro DNA replication and DNA segregation, respectively. These processes were incorporated into biomimetic compartments providing an enclosed reaction space.

Visualizing the inner life of microbes: practices of multi-color single-molecule localization microscopy in microbiology.

In this review, we discuss multi-color single-molecule imaging and tracking strategies for studying microbial cell biology. We first summarize and compare the methods in a detailed literature review of published studies conducted in bacteria and fungi. We then introduce a guideline on which factors and parameters should be evaluated when designing a new experiment, from fluorophore and labeling choices to imaging routines and data analysis.

A Single-Molecule View of Archaeal Transcription.

The discovery of the archaeal domain of life is tightly connected to an in-depth analysis of the prokaryotic RNA world. In addition to Carl Woese's approach to use the sequence of the 16S rRNA gene as phylogenetic marker, the finding of Karl Stetter and Wolfram Zillig that archaeal RNA polymerases (RNAPs) were nothing like the bacterial RNAP but are more complex enzymes that resemble the eukaryotic RNAPII was one of the key findings supporting the idea that archaea constitute the third major branch on the tree of life. This breakthrough in transcriptional research 40years ago paved the way for in-depth studies of the transcription machinery in archaea.

From single bacterial cell imaging towards single-molecule biochemistry studies.

Bacteria as single-cell organisms are important model systems to study cellular mechanisms and functions. In recent years and with the help of advanced fluorescence microscopy techniques, immense progress has been made in characterizing and quantifying the behavior of single bacterial cells on the basis of molecular interactions and assemblies in the complex environment of live cultures. Importantly, single-molecule imaging enables the determination of the stoichiometry and molecular architecture of subcellular structures, yielding detailed, quantitative, spatiotemporally resolved molecular maps and unraveling dynamic heterogeneities and subpopulations on the subcellular level.

Awakening the Sleeping Carboxylase Function of Enzymes: Engineering the Natural CO-Binding Potential of Reductases.

Developing new carbon dioxide (CO) fixing enzymes is a prerequisite to create new biocatalysts for diverse applications in chemistry, biotechnology and synthetic biology. Here we used bioinformatics to identify a "sleeping carboxylase function" in the superfamily of medium-chain dehydrogenases/reductases (MDR), i.e.