Potassium Ion Transport Research Articles

Phenotypic and genomic comparison of dominant and nondominant sequence-type of Acinetobacter baumannii isolated in China.

A. baumannii is a common clinical pathogen that often causes pneumonia and bloodstream infections in ICU patients. Sequence types (ST) are used to investigate the distribution and spread of A. baumannii. Biological characteristics such as virulence and resistance may play a role in A. baumannii becoming a specific dominant ST(DST,ST191, ST195 and ST208) strain. To characterize the biological, genetic, and transcriptomic differences between the DST and non-dominant ST(NST,ST462 and ST547,etc.) strains in A. baumannii, we performed several biological experiments and genetic, and transcriptomic analyses. The DST group displayed more resistance ability to desiccation, oxidation, multiple antibiotics, and complement killing than the NST group. However, the latter had higher biofilm formation ability than the former. The genomic analysis showed the DST group exhibited more capsule-related and aminoglycoside-resistant genes. Besides, GO analysis indicated that functions involved in lipid biosynthetic, transport, and the metabolic process were up-regulated in the DST group, while KEGG analysis manifested that the two-component system related to potassium ion transport and pili were down-regulated. In short, resistance to desiccation, oxidation, multiple antibiotics, and serum complement killing are important reasons for the formation of DST. Genes related to capsule synthesis and lipid biosynthesis and metabolism play an important role at the molecular level in the formation of DST.

Effect of the large-conductance calcium-dependent k<sup>+</sup> channel activator NS1619 on the function of mitochondria in the heart of dystrophin-deficient mice

Dystrophin-deficient muscular dystrophy (Duchenne dystrophy) is characterized by impaired ion homeostasis, in which mitochondria play an important role. In the present work, using a model of dystrophin-deficient mdx mice, we revealed a decrease in the efficiency of potassium ion transport and the total content of this ion in heart mitochondria. We evaluated the effect of chronic administration of the benzimidazole derivative NS1619, which is an activator of the large-conductance Ca2+-dependent K+ channel (mitoBKCa) on the structure and function of organelles and the state of the heart muscle. It was shown that NS1619 improves K+ transport and increases the content of the ion in the heart mitochondria of mdx mice, but this is not associated with changes in the level of the mitoBKCa protein and the expression of the encoding gene. The effect of NS1619 was accompanied by a decrease in the intensity of oxidative stress, assessed by the level of lipid peroxidation products (MDA products) and normalization of the mitochondrial ultrastructure in the heart of mdx mice. In addition, we found positive changes in the tissue, expressed in a decrease in the level of fibrosis in the heart of dystrophin-deficient animals treated with NS1619. It was noted that NS1619 had no significant effect on the structure and function of heart mitochondria in wild-type animals. The paper discusses the mechanisms of influence of NS1619 on the function of mouse heart mitochondria in Duchenne muscular dystrophy and the prospects for applying this approach to correct pathology.

The Effect of Decreased Ca++/Mg++ ATPase Activity on Lactobacillus delbrueckii subsp. bulgaricus sp1.1 Survival during Spray Drying.

Compared with the commonly used technique of freeze-drying, spray drying has lower energy costs. However, spray drying also has a fatal disadvantage: a lower survival rate. In this study, the survival of bacteria in a spray-drying tower decreased as the water content was reduced. The water content of 21.10% was the critical point for spray drying Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) sp1.1 based on sampling in the tower. Based on the relationship between the moisture content of spray drying and the survival rate, the water content of 21.10% was also the critical point for the change in the survival rate during spray drying. Proteomic analysis was used to investigate the reasons for L. bulgaricus sp1.1 inactivation during and after spray drying. Gene Ontology (GO) enrichment revealed that differentially expressed proteins were mainly associated with the cell membrane and transport. In particular, proteins related to metal ion transport included those involved in the transport of potassium, calcium and magnesium ions. The protein-protein interaction (PPI) network revealed that Ca++/Mg++ adenosine triphosphatase (ATPase) may be a key protein. Ca++/Mg++ ATPase activity decreased substantially during spray drying (p < 0.05). Supplementation with Ca++ and Mg++ significantly increased the expression of ATPase-related genes and enzyme activity (p < 0.05). The Ca++/Mg++ ATPase activity of L. bulgaricus sp1.1 was enhanced by increasing the intracellular Ca++ or Mg++ concentration, thus increasing the survival of spray-dried LAB. Bacterial survival rates were increased to 43.06% with the addition of Ca++ and to 42.64% with the addition of Mg++, respectively. Ca++/Mg++ ATPase may be the key to the damage observed in spray-dried bacteria. Furthermore, the addition of Ca++ or Mg++ also reduced bacterial injury during spray drying by enhancing the activity of Ca++/Mg++ ATPase.

Bimetal heterostructure NiCo2Se4 anode confined by carbon nano boxes for ultrafast and stable potassium storage

Transition metal selenides (TMSes) are regarded as promising anodes for potassium ion batteries (PIBs) benefit from their high theoretical capacity. However, the slow kinetics of potassium ion transport, poor charge transfer ability and short cycle life limit the development of transition metal selenide anode. In this article, the dice-shaped NiCo2Se4@N-doped carbon (NCS@NC) nanocomposite is designed for efficient and stable potassium storage. The in-situ formed carbon shell can not only act as a highly conductive framework to accelerate charge transfer, but also limit the volume fluctuation caused by the potassium ion repeated insertion/ extraction process. The in-situ and ex-situ characterization as well as theoretical calculation show that the heterogeneous interface formed by the heterogeneous metal species in NCS@NC spontaneously establish internal electric fields, which significantly accelerates the ion transport. As results, advanced NCS@NC anode with greatly enhanced electrochemical performance is obtained due to the synergy between the three-dimensional structure design and the heterogeneous interface strategy. NCS@NC anode displays extraordinary rate capacity (471.9 mAh g-1 at 2 A g-1) and ultralong cycle life at high current density (454.5 mAh g-1 at 2 A g-1 after 1000 cycles), which indicates that our modification strategy provides an alternative solution for designing advanced PIBs anodes.

Tuning interactions in nanopore arrays with charges on the pore walls

Physiological processes at the cellular level are regulated by nanoconfined ionic transport. Protein channels regulate the passage of specific ions into and out of the cell, and biological systems rely on the concerted function of many channels embedded in their membranes. For instance, the propagation of an action potential down an axon is moderated by the coordinated transport of sodium and potassium ions across neuronal membranes. Beyond its ubiquity in biological systems, transport across nanoporous devices has industrial applications such as single-molecule sensing, energy storage, and water desalination. While single nanopore systems have been thoroughly studied in both biological and industrial contexts, systems containing an array of multiple nanopores are of increasing interest. Due to the close proximity of channels in an array, local environmental changes at the interface of one channel may influence the transport properties of neighboring channels. In this work, we fabricated nanopore arrays with tunable geometries and surface chemistries to probe this cross-talk between nanopores. We employed electron beam sculpting of silicon nitride membranes to fabricate arrays containing two and three nanopores. This method allowed us to engineer devices of varying interpore distances to probe neighboring interactions as a function of interpore distance. Using electrochemical methods, we characterized the current-voltage response of each array at varying sizes of the electric double layer to probe the nature of interpore interactions. Furthermore, we explored surface modifications to create nanopores with bipolar surface charge distributions, which effectively act as ionic diodes. Our results are also complemented by computational modeling. An exploration of the electrokinetic phenomena of these arrays will deepen our understanding of the interplay between neighboring channels, elucidating the mechanisms behind ionic sieving on the scale of an entire network of nanopores.

Expression Profiles, Prognosis, and ceRNA Regulation of SRY-Related HMG-Box Genes in Stomach Adenocarcinoma.

Aberrant expression of the SRY-related HMG-box (SOX) genes contributes to tumor development and progression. This research aimed to identify the regulation of the SOX genes in stomach adenocarcinoma (STAD). Expression profiles downloaded from The Cancer Genome Atlas (TCGA) were conducted to analyze the expression and function of the SOX genes. A competing endogenous RNAs (ceRNA) network mediated by the SOX genes was effectively constructed consisting of 64 lncRNAs, 29 miRNAs, and 11 SOX genes based on predicted miRNAs shared by lncRNAs and mRNAs using miRDB, TargetScan, miRTarBase, miRcode, and starBase v2.0. SOX9 was identified as a prognostic signature, which showed the usefulness of diagnosis and prognosis of STAD by the receiver operating characteristic (ROC) and Kaplan-Meier curves. SOX9 was also shown specifically in STAD and identified as highly expressed in the gastrointestinal tract. Gene Ontology (GO) enrichment analysis showed that SOX9 might influence the genes related to the pattern specification process, sodium ion homeostasis, and potassium ion transport, mainly including FEZF1, HOXC13, HOXC10, HOXC9, HOXA11, DPP6, ATP4B, CASQ2, KCNA1, ATP4A, and SFRP1. Furthermore, HOTAIR knockdown, miR-206-mimic transfection, the Cell Count Kit-8 (CCK-8) assay were performed to verify the function of HOTAIR/miR-206/SOX9 axis, which was identified in the ceRNA network analysis. HOTAIR could induce proliferation potentially by competitively binding miR-206/SOX9 axis in STAD. These findings provide new clues with prognostic and therapeutic implications in STAD and suggest that HOTAIR/miR-206/SOX9 might be a potential new strategy for therapeutic targeting of gastric cancer.

Bioinformatics approach to identify the core ontologies, pathways, signature genes and drug molecules of prostate cancer

Prostate cancer (PoC) is currently one of the most frequent cancers in males. Though a lot of work has been done on it, the biomarkers in the progression of prostate cancer have not been fully identified. In this research, we used the GSE70466 and GSE104131 for RNA-Seq gene expression datasets to reveal the important biomarkers and related pathways of prostate cancer. Furthermore, Differentially Expressed Genes (DEGs) were extracted from the dataset with the R statistical language tools, and to investigate the functional enrichment of the DEGs, an online repository Enrichr was used. Then, another database, STRING was used in this work to generate the protein-protein interaction (PPI) network and represented the network using the well-known Cytoscape software. After that, a Cystoscape plug-in MCODE identified clusters from the PPI network. In the end, some drug compounds that may be useful in the therapy of PoC have been revealed. A total of 83 common DEGs (43 upregulated and 40 downregulated) were exposed using some statistical criteria. Overexpressed DEGs were engaged in the metabolism of glutamine family amino acids and alpha-amino acids, while underexpressed DEGs were mostly involved in the regulation of the transmembrane receptor protein serine/threonine kinase signaling pathway and positive regulation of potassium ion transport. In addition, the overexpressed DEGs were highly involved with Arginine and Proline metabolism, whereas the underexpressed DEGs were connected with Proteoglycans in cancer, according to the KEGG pathway analysis. A total of 154 nodes and 2068 connections were used to construct the PPI. Using the connectivity method, we conclude 20 genes (INS; VEGFA; CDH1; IGF1; ITGB1; IGF1R; CAV1; ESR1; KDR; TGFB1; CD44; MMP9; PIK3R1; SHC1; IGF2; SMAD4; TGFBR1; ENG; IRS1; VWF) as hub genes. Finally, we identified and validated two important biomarkers as well as certain pharmacological compounds that could be effective in the therapy of PoC.

A mushroom derived biomass carbon as high-stability anode for potassium ion battery

As an alternative to Li-ion batteries, potassium-ion batteries have attracted increasing research interest due to the natural abundance of potassium and low cost. However, the larger ionic radius of the potassium easily causes a large volume expansion of the anode materials, eventually hindering the practical application of potassium-ion batteries. Here, we reported a heteroatomic doping mushroom biomass carbon (HDMC) as anode material for potassium-ion batteries. With high surface area and rich heteroatomic doping (N, S, and P), the as-prepared porous HDMC not only provides sufficient void space to relieve volume expansion of electrode but also offers highly efficient channels for fast transport of both electrons and potassium ions. The results demonstrated that the HDMC showed relatively high specific capacity (290 mAh g−1 at 500 mA g−1) and outstanding cycling stability after 2000 cycles. In-situ Raman spectroscopy and galvanostatic intermittent titration confirmed its surface-dominated potassium storage behavior with fast de-/potassiation kinetics, satisfactory reversibility, and fast ion/electron transport. This work guides an effective bionic strategy for the preparation of biomass carbon as high-performance anode materials.

Realized potential as neutral pH flow batteries achieve high power densities

High power density operation of redox flow batteries (RFBs) is essential for lowering system costs, but until now, only acid-based chemistries have achieved such performance, primarily due to rapid membrane proton (H + ) transport. Here, we report a neutral pH RFB using the highly reducing Cr-(1,3-propylenediaminetetraacetate) (CrPDTA) complex that achieves acid-like power performance while utilizing potassium ion (K + ) transport. We investigate RFB resistance components and demonstrate the high and consistent K + conductivity of the Fumasep E-620(K) membrane. When combined with a robust bismuth electrocatalyst, this membrane enables constant voltage efficiency operation of a CrPDTA|Fe(CN) 6 RFB for 200 cycles. An optimized CrPDTA|Fe(CN) 6 RFB, which combines a high cell potential with a low area-specific resistance (0.46 Ω cm 2 ), demonstrates a maximum discharge power density of 1.63 W cm −2 and an average discharge power density over 500 mW cm −2 while maintaining 80% round-trip energy efficiency cycling, which are records for non-acid-based RFBs. • High-power flow battery operates at neutral pH with potassium membrane transport • Record discharge-power performance for a flow battery not using proton transport • Inexpensive membrane provides high conductivity and constant efficiency cycling • Chelated metal electrolyte enables high voltage battery and high-power operation High-power flow battery operation lowers system costs but has previously required proton transport. By combining high voltage with low resistance from a highly selective and conductive membrane, Robb et al. demonstrate an aqueous flow battery that achieves record non-acidic power performance while utilizing potassium membrane transport at neutral pH.

Comprehensive Analysis of Transcriptome and Metabolome Elucidates the Molecular Regulatory Mechanism of Salt Resistance in Roots of Achnatherum inebrians Mediated by Epichloë gansuensis

Salinization of soil is a major environmental risk factor to plant functions, leading to a reduction of productivity of crops and forage. Epichloë gansuensis, seed-borne endophytic fungi, establishes a mutualistic symbiotic relationship with Achnatherum inebrians and confers salt tolerance in the host plants. In this study, analysis of transcriptome and metabolome was used to explore the potential molecular mechanism underlying the salt-adaptation of A. inebrians roots mediated by E. gansuensis. We found that E. gansuensis played an important role in the gene expression of the host’s roots and regulated multiple pathways involved in amino acid metabolism, carbohydrate metabolism, TCA cycle, secondary metabolism, and lipid metabolism in the roots of A. inebrians. Importantly, E. gansuensis significantly induced the biological processes, including exocytosis, glycolytic process, fructose metabolic process, and potassium ion transport in roots of host plants at transcriptional levels, and altered the pathways, including inositol phosphate metabolism, galactose metabolism, starch, and sucrose metabolism at metabolite levels under NaCl stress. These findings provided insight into the molecular mechanism of salt resistance in roots of A. inebrians mediated by E. gansuensis and could drive progress in the cultivation of new salt-resistance breeds with endophytes.

TRY 4: A high yielding, mid early sodicity tolerant rice variety suited to Tamil Nadu

Sodicity tolerant rice culture TR 05031, a derivative of the cross ADT 39 x CO 45&nbsp; was released as Rice TRY 4 during the year 2021 as a mid early duration variety&nbsp; with 127 days duration with high yield, &nbsp;high milling (68.1 %)&nbsp; and head rice recovery (57.2 %). Twelve years of testing across 181 locations in Tamil Nadu revealed that the culture&nbsp; is &nbsp;high yielding (5730 kg/ha with 22.00 per cent increased grain yield over TKM 13 and 16.50 per cent over ADT 39) in salt affected soils. EDAX under SEM studies confirmed that, there was a lesser transport of sodium ions and higher transport of potassium ions from root to shoot in this culture, TR05031. Besides,&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TR05 031 maintain more tracheids /unit leaf area and accumulate salts to the outer epidermal layer through specialized trichomes, providing resistance to salinity. The culture TR05031 is resistant to major diseases viz., blast and brown spot and has field resistance to major pests viz., leaffolder, stem borer and gall midge. &nbsp;TR05031 with high yield, better pest and disease resistance and good cooking quality is suitable for cultivation during late samba/thaladi in salt affected patches of Tamil Nadu. The culture was released as TRY 4 during 2021 and notified by Government of India for seed production. &nbsp;Keywords: Rice, TRY 4, variety, mid early, sodicity tolerance

The Effect of Uridine on the State of Skeletal Muscles and the Functioning of Mitochondria in Duchenne Dystrophy.

Duchenne muscular dystrophy is caused by the loss of functional dystrophin that secondarily causes systemic metabolic impairment in skeletal muscles and cardiomyocytes. The nutraceutical approach is considered as a possible complementary therapy for this pathology. In this work, we have studied the effect of pyrimidine nucleoside uridine (30 mg/kg/day for 28 days, i.p.), which plays an important role in cellular metabolism, on the development of DMD in the skeletal muscles of dystrophin deficient mdx mice, as well as its effect on the mitochondrial dysfunction that accompanies this pathology. We found that chronic uridine administration reduced fibrosis in the skeletal muscles of mdx mice, but it had no effect on the intensity of degeneration/regeneration cycles and inflammation, pseudohypetrophy, and muscle strength of the animals. Analysis of TEM micrographs showed that uridine also had no effect on the impaired mitochondrial ultrastructure of mdx mouse skeletal muscle. The administration of uridine was found to lead to an increase in the expression of the Drp1 and Parkin genes, which may indicate an increase in the intensity of organelle fission and the normalization of mitophagy. Uridine had little effect on OXPHOS dysfunction in mdx mouse mitochondria, and moreover, it was suppressed in the mitochondria of wild type animals. At the same time, uridine restored the transport of potassium ions and reduced the production of reactive oxygen species; however, this had no effect on the impaired calcium retention capacity of mdx mouse mitochondria. The obtained results demonstrate that the used dose of uridine only partially prevents mitochondrial dysfunction in skeletal muscles during Duchenne dystrophy, though it mitigates the development of destructive processes in skeletal muscles.

Bitumen-Derived Onion-Like Soft Carbon as High-Performance Potassium-Ion Battery Anode.

Potassium-ion batteries (PIBs) have been regarded as a competitive alternative for lithium-ion batteries, owing to the natural abundance, low cost, and similar rocking-chair working mechanism of potassium element. However, it is challenging to simultaneously prepare suitable potassium ion anode materials of low voltage plateau, high capacity, and long cycle life. In this work, onion-like soft carbon (OLSC) of high heteroatom content is prepared by using solvent-sensitive self-assembly properties of asphaltene molecules. The OLSC electrode exhibits a low voltage plateau because of a high degree of graphitization. Meanwhile, it possesses excellent cycling stability and rate capability due to the high stability of the onion-like structure and fast transport of potassium ions, the latter of which is caused by heteroatom-induced expanded interlayers as found by first-principle calculations. Compared with existing carbon materials, the OLSC synthesized in this study exhibits a high reversible capacity of 466mAhg-1 at 20mAg-1 , a reversible capacity of 222mAhg-1 and capacity retention of 95% after 1600 cycles at 1Ag-1 . This work connects the nanostructure of carbon materials and electrochemical performance and provides new insights in improving carbon-based anodes for PIBs.

Fabrication of Fe3C nanoparticles embedded in N-doped carbon nanotubes/porous carbon 3D materials derived from distilled grains for high performance of potassium ion battery

The design and fabrication of advanced carbon materials is highly important for potassium ion batteries. In this paper, Fe 3 C nanoparticles embedded in N-doped carbon nanotubes/porous carbon (Fe 3 C@N-CNPC) 3D materials were synthesized by pyrolysis of N-doped distilled grains in the presence of FeCl 3 /ZnCl 2 activators. It was demonstrated that the FeCl 3 /ZnCl 2 activators played an important role in the formation of Fe 3 C@N-CNPC 3D materials. On the one hand, the activator endowed the carbonaceous materials with a high proportion of micropores and large surface area. On the other hand, Fe nanoparticles generated by decomposition of FeCl 3 catalyzed the growth of intertwined carbon nanotubes on porous carbon, yielding Fe 3 C@N-CNPC 3D materials with abundant porous structure and a high degree of graphitization. The as-prepared Fe 3 C@N-CNPC were used as anode materials for potassium ion batteries. Due to the synergistic effect of N-doping, superstructure, and large surface area, the Fe 3 C@N-CNPC based potassium ion batteries exhibited remarkable potassium storage capacity (273 mAh g −1 at 100 mA g −1 ) and excellent cycle stability (94% capacity retention at 100 mA g −1 after 570 cycles). This novel carbon material with low cost and ease preparation is of great significance for the application of potassium ion batteries. Meanwhile, our strategy also provides a reference idea for the resource utilization of the distilled grains waste. • N-doped carbon nanotubes/porous carbons were prepared by nitrogen doping and chemical catalysis processes. • The presence of the activator ferric chloride determines the formation of carbon nanotubes. • The carbon nanotubes effectively increase the specific surface area and graphitization degree of the material. • The N-doped carbon nanotubes/porous carbon provides support for the fast transport and stable storage of potassium ions.

Supramolecular Mechanosensitive Potassium Channel Formed by Fluorinated Amphiphilic Cyclophane.

Inspired by mechanosensitive potassium channels found in nature, we developed a fluorinated amphiphilic cyclophane composed of fluorinated rigid aromatic units connected via flexible hydrophilic octa(ethylene glycol) chains. Microscopic and emission spectroscopic studies revealed that the cyclophane could be incorporated into the hydrophobic layer of the lipid bilayer membranes and self-assembled to form a supramolecular transmembrane ion channel. Current recording measurements using cyclophane-containing planer lipid bilayer membranes successfully demonstrated an efficient transmembrane ion transport. We also demonstrated that the ion transport property was sensitive to the mechanical forces applied to the membranes. In addition, ion transport assays using pH-sensitive fluorescence dye revealed that the supramolecular channel possesses potassium ion selectivity. We also performed all-atom hybrid quantum-mechanical/molecular mechanical simulations to assess the channel structures at atomic resolution and the mechanism of selective potassium ion transport. This research demonstrated the first example of a synthetic mechanosensitive potassium channel, which would open a new door to sensing and manipulating biologically important processes and purification of key materials in industries.

Comparison of Fecundity Traits between Mauremys reevesii and Trachemys scripta based on Gene Family Analysis

Background: Chinese pond turtle (CPT, Mauremys reevesii) is a typical species with temperature-dependent sex determination (TSD). Pond slider turtle (PST, Trachemys scripta) is considered one of the worst invasive species in the world. In order to analyze the adaptive evolution of fecundity traits in CPT and TSD, the rapidly evolving gene families were obtained and functional enrichment analysis was performed. At the same time, CPT and PST species-specific genes were also enriched for their fecundity traits. Methods: Orthofinder software was employed to search homologous genes based on protein sequence. CAFÉ software was used to obtain the expansion and contraction gene families of CPT and PST. Then, GO terms and pathway enrichment analyses were performed using TBtools software and Swissprot database. Result: In CPT, 159 rapid expansion gene families GO enrichment results showed that the reproductive activities related pathways were mainly three significant enrichment process, spermatogenesis, steroid hormone mediated signaling pathway and male gamete generation. 2 rapidly contraction gene families showed that there was no significant enrichment pathway related to reproduction. The pathway of significant enrichment were RNA biosynthetic process, regulation of RNA metabolic process and regulation of cellular metabolic process. The gene families unique to the species were significantly enriched in pathways DNA replication-dependent nucleosome organization, DNA replication-dependent nucleosome assembly and negative regulation of megakaryocyte differentiation. In PST, 15 rapid expansion gene families GO enrichment results showed that the most significant GO terms mainly consisted of biological processes which were involved in endocrine process, regulation of endocrine process and cellular response to steroid hormone stimulus, but spermatogenesis and male gamete generation gene families also expanded. 58 rapidly contraction gene families showed that the pathways of significant enrichment were endocrine process, cellular response to steroid hormone stimulus and regulation of endocrine process. At the same time, estrogen secretion, binding of sperm to zona pellucida and sperm-egg recognition gene family also rapidly contraction. The gene families unique to the species were significantly enriched in pathways adenylate cyclase-activating G protein-coupled receptor signaling pathway, double-strand break repair and regulation of potassium ion transport.

New nanostructured extracellular potassium ion probe for assay of cellular K+ transport

The concentration of potassium ion is an important indicator for human health, and its abnormality is often accompanied by various diseases. However, most tools currently used to study potassium ion transport are low throughput. Herein, we reported a new K+ fluorescent nanoprobe CP1-KS with high selectivity and sensitivity to K+ (fluorescence enhanced factor was up to 9.91 at 20 mM K+). The polymeric fluorescent probe CP1-KS was composed of the small-molecular K+ indicator KS and amphiphilic copolymer CP1. This sensor can be easily and uniformly dispersed in cell culture medium and is suitable for high throughput analysis. To assess the utility of the probe CP1-KS in biological field, this probe was employed as an extracellular fluorescent probe to monitor the efflux of K+ from cells (E coli, B. Subtilis 168, Hela and MCF-7 cells) under various stimulation including lysozyme, nigericin, digitonin, and ATP. Results demonstrated that CP1-KS is an effective analysis tool for extracellular K+ concentration. We believe that the nanoprobe has great potential in antibacterial drug screening, K+ ionophore function, K+ channel activity, cell membrane permeability analysis or other K+ related field in the future.

Exploiting the antibacterial mechanism of phenazine substances from Lysobacter antibioticus 13-6 against Xanthomonas oryzae pv. oryzicola.

Bacterial leaf streak caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most destructive diseases affecting rice production worldwide. In this study, we extracted and purified phenazine substances from the secondary metabolites of Lysobacter antibioticus 13-6. The bacteriostatic mechanism of phenazine substances against Xoc was investigated through physiological response and transcriptomic analysis. Results showed that phenazine substances affects the cell membrane permeability of Xoc, which causes cell swelling and deformation, blockage of flagellum synthesis, and imbalance of intracellular environment. The changes in intracellular environment affect the physiological and metabolic functions of Xoc, which reduces the formation of pathogenic factors and pathogenicity. Through transcriptomic analysis, we found that among differentially expressed genes, the expression of 595 genes was induced significantly (275 up-regulated and 320 down-regulated). In addition, we observed that phenazine substances affects three main functions of Xoc, i.e., transmembrane transporter activity, DNA-mediated transposition, and structural molecular activity. Phenazine substances also inhibits the potassium ion transport system that reduces Xoc resistance and induces the phosphate ion transport system to maintain the stability of the internal environment. Finally, we conclude that phenazine substances could retard cell growth and reduce the pathogenicity of Xoc by affecting cell structure and physiological metabolism. Altogether, our study highlights latest insights into the antibacterial mechanism of phenazine substances against Xoc and provides basic guidance to manage the incidence of bacterial leaf streak of rice.

Molecular-genetic characterization of halotolerant strain &lt;i&gt;Priestia megaterium&lt;/i&gt; BIM B-1314D

Priestia megaterium BIM В‑1314D is a halotolerant strain able to adapt to osmotic stress. The analysis of a full nucleotide sequence of bacterium P. megaterium BIM В‑1314D has revealed that the genome of the studied strain is represented by one circular chromosome and nine plasmids, deposited in the database of GenBank NCBI under the registration number CP058262–CP058271. The size of the bacterial genome constitutes 5 984 922 base pairs with an average GC content of 37.7 %. The genome contains 6 187 genes where 5 978 were annotated as protein-enconding, 92 – as pseudogenes, 154 – as tRNA genes, 8 – as ncRNA, 47 – as rRNA. The genes responsible for synthesis and transport of betaine and proline osmolytes and transport of potassium ions ensuring the adaptation of strain P. megaterium BIM В‑1314D to osmotic stress were local-ized in the genome. Gene loci were defined encoding production of metabolites involved in the synthesis of phytohormones and polyamines accounting for the growth-promoting microbial ability. Gene clusters determining the synthesis of secondary metabolites, cold and heat shock proteins were revealed in the genome. The genome analysis of strain P. megaterium BIM В‑1314D provides the valuable data on the bacterial culture for stimulation of the plant growth in the salinized conditions.

Rate of translocation across lipid bilayer of triphenylphosphonium-linked salinomycin derivatives contributes significantly to their K+/H+ exchange activity on membranes

Salinomycin (SAL), a polyether antibiotic exerting K+/H+-exchange on cellular membranes, effectively kills cancer stem cells. A series of cationic triphenylphosphonium (TPP+)-linked SAL derivatives were synthesized aiming to render them mitochondria-targeted. Remarkably, attaching a TPP+ moiety via a triazole linker at the C-20 position of SAL (compound 5) preserved the ion carrier potency of the antibiotic, while analogs with TPP+ linked at the C-1 position of SAL (6, 8) were ineffective. On planar bilayer lipid membranes (BLM), the SAL analogs 6 and 8 exhibited slow electrical current relaxation upon a voltage jump, similar to previously studied alkyl-TPP compounds. However, 5 demonstrated much faster current relaxation, which suggested its high permeability through BLM resulting in its pronounced potency to transport potassium and hydrogen ions across both artificial (liposomal) and mitochondrial membranes. SAL and 5 did not induce a steady-state electrical current through the planar lipid bilayer, thereby confirming that the transport mechanism is the electrically silent K+/H+ exchange. The ion exchange mediated by 5 in energized mitochondria was more active than that caused by SAL, which was apparently due to accumulation of 5 in mitochondria. Thus, compound 5 can be regarded as a promising lead compound for testing anticancer and antimicrobial activity.