The Pkn22 Kinase of Nostoc PCC 7120 Is Required for Cell Differentiation via the Phosphorylation of HetR on a Residue Highly Conserved in Genomes of Heterocyst-Forming Cyanobacteria

Hanks-type kinases encoding genes are present in most cyanobacterial genomes. Despite their widespread pattern of conservation, little is known so far about their role because their substrates and the conditions triggering their activation are poorly known. Here we report that under diazotrophic conditions, normal heterocyst differentiation and growth of the filamentous cyanobacterium Nostoc PCC 7120 require the presence of the Pkn22 kinase, which is induced under combined nitrogen starvation conditions. By analyzing the phenotype of pkn22 mutant overexpressing genes belonging to the regulatory cascade initiating the development program, an epistatic relationship was found to exist between this kinase and the master regulator of differentiation, HetR. The results obtained using a bacterial two hybrid approach indicated that Pkn22 and HetR interact, and the use of a genetic screen inducing the loss of this interaction showed that residues of HetR which are essential for this interaction to occur are also crucial to HetR activity both in vitro and in vivo. Mass spectrometry showed that HetR co-produced with the Pkn22 kinase in Escherichia coli is phosphorylated on Serine 130 residue. Phosphoablative substitution of this residue impaired the ability of the strain to undergo cell differentiation, while its phosphomimetic substitution increased the number of heterocysts formed. The Serine 130 residue is part of a highly conserved sequence in filamentous cyanobacterial strains diff...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research

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Ribosomal RNAs in all organisms are methylated. The functional role of the majority of modified nucleotides is unknown. We systematically questioned the influence of rRNA methylation in Escherichia coli on a number of characteristics of bacterial cells with the help of a set of rRNA methyltransferase (MT) gene knockout strains from the Keio collection. Analysis of ribosomal subunits sedimentation profiles of the knockout strains revealed a surprisingly small number of rRNA MT that significantly affected ribosome assembly. Accumulation of the assembly intermediates was observed only for the rlmE knockout strain whose growth...
Source: Frontiers in Genetics - Category: Genetics & Stem Cells Source Type: research
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Source: Health News: - Category: Consumer Health News Source Type: news
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Source: WebMD Health - Category: Consumer Health News Source Type: news
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Source: Healthcare News - Category: Pharmaceuticals Authors: Source Type: news
Influence of miR-155 on behaviors of depression mice through regulating Wnt/β-catenin signaling pathway. Eur Rev Med Pharmacol Sci. 2020 Feb;24(3):1398-1407 Authors: Dai J, Pan JY, Liao N, Shi J, Zeng Q, Huang L, Chen LP Abstract OBJECTIVE: To study the influence of micro ribonucleic acid (miR)-155 on depression-like behaviors of depression mice, and to explore the role of Wnt/b-catenin signaling pathway in behavioral regulation of depression mice. MATERIALS AND METHODS: The mouse model of depression was established via chronic unpredictable mild stress (CUMS). All mice were randomly divided i...
Source: European Review for Medical and Pharmacological Sciences - Category: Drugs & Pharmacology Tags: Eur Rev Med Pharmacol Sci Source Type: research
The U.S. Food and Drug Administration has issued a warning letter to sandwich chain Jimmy John's, accusing the company of selling fresh produce linked to five outbreaks of E. coli or salmonella in the past seven years.
Source: Health News - - Category: Consumer Health News Source Type: news
Contributors : A K Sharma ; J ShiloachSeries Type : Expression profiling by arrayOrganism : Escherichia coliWe used microarray to identify the global gene expression profile of recombinant E.coli culture expressing repeating unit of the C. difficile toxin A (rARU) C-terminal region. Controlled condition batch runs were performed with E.coli expressing rARU at both restricted and unrestricted DO conditions for collecting samples of log and late-log phases at unrestricted and restricted DO.
Source: GEO: Gene Expression Omnibus - Category: Genetics & Stem Cells Tags: Expression profiling by array Escherichia coli Source Type: research
Publication date: Available online 25 February 2020Source: Process BiochemistryAuthor(s): Sha Xu, Qin Wang, Weizhu Zeng, Youran Li, Guiyang Shi, Jingwen Zhou
Source: Process Biochemistry - Category: Biochemistry Source Type: research
The composting ecosystem provides a potential resource for finding new microorganisms with the capability for cellulose degradation. In the present study, Congo red method was used for the isolating of thermostable lignocellulose-degrading bacteria from chicken manure compost. A thermophilic strain named as Geobacillus thermodenitrificans Y7 with acid-resident property was successfully isolated and employed to degrade raw switchgrass at 60°C for 5 days, which resulted in the final degradation rates of cellulose, xylan, and acid-insoluble lignin as 18.64, 12.96, and 17.21%, respectively. In addition, GC-MS analysis abou...
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research
Hasbullah A novel label-free electrochemical DNA biosensor was constructed for the determination of Escherichia coli bacteria in environmental water samples. The aminated DNA probe was immobilized onto hollow silica microspheres (HSMs) functionalized with 3-aminopropyltriethoxysilane and deposited onto a screen-printed electrode (SPE) carbon paste with supported gold nanoparticles (AuNPs). The biosensor was optimized for higher specificity and sensitivity. The label-free E. coli DNA biosensor exhibited a dynamic linear response range of 1 × 10−10 µM to 1 × 10−5 &mic...
Source: Sensors - Category: Biotechnology Authors: Tags: Article Source Type: research
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