Identification,Quantification, and System Analysis of Protein N‐ε Lysine Methylation in Anucleate Blood Platelets

Protein posttranslational modifications critically regulate a range of physiological and disease processes. In addition to tyrosine, serine, and threonine phosphorylation, reversible N‐ε acylation and alkylation of protein lysine residues also modulate diverse aspects of cellular function. Studies of lysine acyl and alkyl modifications have focused on nuclear proteins in epigenetic regulation; however, lysine modifications are also prevalent on cytosolic proteins to serve increasingly apparent, although less understood roles in cell regulation. Here, the methyl‐lysine (meK) proteome of anucleate blood platelets is characterized. With high‐resolution, multiplex MS methods, 190 mono‐, di‐, and tri‐meK modifications are identified on 150 different platelet proteins—including 28 meK modifications quantified by tandem mass tag (TMT) labeling. In addition to identifying meK modifications on calmodulin (CaM), GRP78 (HSPA5, BiP), and EF1A1 that have been previously characterized in other cell types, more novel modifications are also uncovered on cofilin, drebin‐like protein (DBNL, Hip‐55), DOCK8, TRIM25, and numerous other cytoplasmic proteins. Together, the results and analyses support roles for lysine methylation in mediating cytoskeletal, translational, secretory, and other cellular processes. MS data for this study have been deposited into the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD012217.     

In‐Cell NMR Spectroscopy of Intrinsically Disordered Proteins

This review summarizes the results of in‐cell Nuclear Magnetic Resonance, NMR, spectroscopic investigations of the eukaryotic and prokaryotic intrinsically disordered proteins, IDPs: α‐synuclein, prokaryotic ubiquitin‐like protein, Pup, tubulin‐related neuronal protein, Tau, phenylalanyl‐glycyl‐repeat‐rich nucleoporins, FG Nups, and the negative regulator of flagellin synthesis, FlgM. The results show that the cellular behavior of IDPs may differ significantly from that observed in the test tube.     

Fluorine‐Free Noble Salt Anion for High‐Performance All‐Solid‐State Lithium–Sulfur Batteries

Amongst post‐Li‐ion battery technologies, lithium–sulfur (Li–S) batteries have captured an immense interest as one of the most appealing devices from both the industrial and academia sectors. The replacement of conventional liquid electrolytes with solid polymer electrolytes (SPEs) enables not only a safer use of Li metal (Li°) anodes but also a flexible design in the shape of Li–S batteries. However, the practical implementation of SPEs‐based all‐solid‐state Li–S batteries (ASSLSBs) is largely hindered by the shuttling effect of the polysulfide intermediates and the formation of dendritic Li° during the battery operation. Herein, a fluorine‐free noble salt anion, tricyanomethanide [C(CN)₃^?, TCM^?], is proposed as a Li‐ion conducting salt for ASSLSBs. Compared to the widely used perfluorinated anions {e.g., bis(trifluoromethanesulfonyl)imide anion, [N(SO₂CF₃)₂)]^?, TFSI^?}, the LiTCM‐based electrolytes show decent ionic conductivity, good thermal stability, and sufficient anodic stability suiting the cell chemistry of ASSLSBs. In particular, the fluorine‐free solid electrolyte interphase layer originating from the decomposition of LiTCM exhibits a good mechanical integrity and Li‐ion conductivity, which allows the LiTCM‐based Li–S cells to be cycled with good rate capability and Coulombic efficiency. The LiTCM‐based electrolytes are believed to be the most promising candidates for building cost‐effective and high energy density ASSLSBs in the near future.     

Characterization of the mitochondrial genome of the MAX1 type of cytoplasmic male-sterile sunflower

Background

More than 70 cytoplasmic male sterility (CMS) types have been identified in Helianthus, but only for less than half of them, research of mitochondrial organization has been conducted. Moreover, complete mitochondrion sequences have only been published for two CMS sources – PET1 and PET2. It has been demonstrated that other sunflower CMS sources like MAX1, significantly differ from the PET1 and PET2 types. However, possible molecular causes for the CMS induction by MAX1 have not yet been proposed. In the present study, we have investigated structural changes in the mitochondrial genome of HA89 (MAX1) CMS sunflower line in comparison to the fertile mitochondrial genome.

Results

Eight significant major reorganization events have been determined in HA89 (MAX1) mtDNA: one 110 kb inverted region, four deletions of 439 bp, 978 bp, 3183 bp and 14,296 bp, respectively, and three insertions of 1999 bp, 5272 bp and 6583 bp. The rearrangements have led to functional changes in the mitochondrial genome of HA89 (MAX1) resulting in the complete elimination of orf777 and the appearance of new ORFs - orf306, orf480, orf645 and orf1287. Aligning the mtDNA of the CMS sources PET1 and PET2 with MAX1 we found some common reorganization features in their mitochondrial genome sequences.

Conclusion

The new open reading frame orf1287, representing a chimeric atp6 gene, may play a key role in MAX1 CMS phenotype formation in sunflower, while the contribution of other mitochondrial reorganizations seems to appear negligible for the CMS development.

     

Changes in presynaptic calcium signalling accompany age‐related deficits in hippocampal LTP and cognitive impairment

The loss of cognitive function accompanying healthy aging is not associated with extensive or characteristic patterns of cell death, suggesting it is caused by more subtle changes in synaptic properties. In the hippocampal CA1 region, long‐term potentiation requires stronger stimulation for induction in aged rats and mice and long‐term depression becomes more prevalent. An age‐dependent impairment of postsynaptic calcium homeostasis may underpin these effects. We have examined changes in presynaptic calcium signalling in aged mice using a transgenic mouse line (SyG37) that expresses a genetically encoded calcium sensor in presynaptic terminals. SyG37 mice showed an age‐dependent decline in cognitive abilities in behavioural tasks that require hippocampal processing including the Barnes maze, T‐maze and object location but not recognition tests. The incidence of LTP was significantly impaired in animals over 18 months of age. These effects of aging were accompanied by a persistent increase in resting presynaptic calcium, an increase in the presynaptic calcium signal following Schaffer collateral fibre stimulation, an increase in postsynaptic fEPSP slope and a reduction in paired‐pulse facilitation. These effects were not caused by synapse proliferation and were of presynaptic origin since they were evident in single presynaptic boutons. Aged synapses behaved like younger ones when the extracellular calcium concentration was reduced. Raising extracellular calcium had little effect on aged synapses but altered the properties of young synapses into those of their aged counterparts. These effects can be readily explained by an age‐dependent change in the properties or numbers of presynaptic calcium channels.     

On the Reversibility and Fragility of Sodium Metal Electrodes

Metallic sodium is receiving renewed interest as a battery anode material because the metal is earth‐abundant, inexpensive, and offers a high specific storage capacity (1166 mAh g^?1 at ?2.71 V vs the standard hydrogen potential). Unlike metallic lithium, the case for Na as the anode in rechargeable batteries has already been demonstrated on a commercial scale in high‐temperature Na||S and Na||NiCl₂ secondary batteries, which increases interest. The reversibility of room temperature sodium anodes is investigated in galvanostatic plating/stripping reactions using in situ optical visualization and galvanostatic polarization measurements. It is discovered that electronic disconnection of mossy metallic Na deposits (“orphaning”) is a dominant source of anode irreversibility in liquid electrolytes. The disconnection is shown by means of direct visualization studies to be triggered by a root‐breakage process during the stripping cycle. As a further step toward electrode designs that are able to accommodate the fragile Na deposits, electrodeposition of Na is demonstrated in nonplanar electrode architectures, which provide continuous and morphology agnostic access to the metal at all stages of electrochemical cycling. On this basis, nonplanar Na electrodes are reported, which exhibit exceptionally high levels of reversibility (Coulombic efficiency >99.6% for 1 mAh cm^?2 Na throughput) in room‐temperature, liquid electrolytes.     

Segregostat: a novel concept to control phenotypic diversification dynamics on the example of Gram-negative bacteria

Controlling and managing the degree of phenotypic diversification of microbial populations is a challenging task. This task not only requires detailed knowledge regarding diversification mechanisms but also advanced technical set-ups for the real-time analyses and control of population behaviour on single-cell level. In this work, set-up, design and operation of the so called segregostat are described which, in contrast to a traditional chemostat, allows the control of phenotypic diversification of microbial populations over time. Two exemplary case studies will be discussed, i.e. phenotypic diversification dynamics of Eschericia coli and Pseudomonas putida based on outer membrane permeabilization, emphasizing the applicability and versatility of the proposed approach. Upon nutrient limitation, cell population tends to diversify into several subpopulations exhibiting distinct phenotypic features (non-permeabilized and permeabilized cells). Online analysis leads to the determination of the ratio between cells in these two states, which in turn triggers the addition of glucose pulses in order to maintain a predefined diversification ratio. These results prove that phenotypic diversification can be controlled by means of defined pulse-frequency modulation within continuously running bioreactor set-ups. This lays the foundation for systematic studies, not only of phenotypic diversification but also for all processes where dynamics single-cell approaches are required, such as synthetic co-culture processes.