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Rules and Exceptions: The Role of Chromosomal ParB in DNA Segregation and Other Cellular Processes
Get PDFAbstract: The segregation of newly replicated chromosomes in bacterial cells is a highly coordinated spatiotemporal process. In the majority of bacterial species, a tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target(s) parS sequence(s), facilitates the initial steps of chromosome partitioning. ParB nucleates around parS(s) located in the vicinity
of newly replicated oriCs to form large nucleoprotein complexes, which are subsequently relocated by ParA to distal cellular compartments. In this review, we describe the role of ParB in various processes within bacterial cells, pointing out interspecies differences. We outline recent progress in understanding the ParB nucleoprotein complex formation and its role in DNA segregation, including
ori positioning and anchoring, DNA condensation, and loading of the structural maintenance of chromosome (SMC) proteins. The auxiliary roles of ParBs in the control of chromosome replication initiation and cell division, as well as the regulation of gene expression, are discussed. Moreover, we
catalog ParB interacting proteins. Overall, this work highlights how different bacterial species adapt the DNA partitioning ParAB-parS system to meet their specific requirements
Valeric Acid, a Gut Microbiota Product, Penetrates to the Eye and Lowers Intraocular Pressure in Rats
Get PDFIncreased activity of the sterol branch of the mevalonate pathway elevates glycosylation of secretory proteins and improves antifungal properties of Trichoderma atroviride.
Get PDFSome Trichoderma spp. have an ability to inhibit proliferation of fungal plant pathogens in the soil. Numerous compounds with a proven antifungal activity are synthesized via the terpene pathway.
Here, we stimulated the activity of the mevalonate pathway in T. atroviride P1 by expressing the Saccharomyces cerevisiae ERG20 gene coding for farnesyl pyrophosphate (FPP) synthase, a key enzyme of this pathway. ERG20-expressing Trichoderma strains showed higher activities of FPP synthase and squalene synthase, the principal recipient of FPP in the mevalonate pathway.
We also observed activation of dolichyl phosphate mannose (DPM) synthase, an enzyme in protein glycosylation, and significantly increased O- and N-glycosylation of secreted proteins. The hyper-glycosylation of secretory hydrolases could explain their increased activity observed in the ERG20 transformants.
Analysis of the antifungal properties of the new strains revealed that the hydrolases secreted by the transformants inhibited growth of a plant pathogen, Pythium ultimum more efficiently compared to the control strain. Consequently, the biocontrol activity of the transgenic strains, determined as their ability to protect bean seeds and seedlings against harmful action of P. ultimum, was also improved substantially
Genome sequence of Pseudomonas aeruginosa PAO1161, a PAO1 derivative with the ICEPae1161 integrative and conjugative element
Get PDFBackground: Pseudomonas aeruginosa is a cause of nosocomial infections, especially in patients with cystic fibrosis
and burn wounds. PAO1 strain and its derivatives are widely used to study the biology of this bacterium, however
recent studies demonstrated differences in the genomes and phenotypes of derivatives from different laboratories.
Results: Here we report the genome sequence of P. aeruginosa PAO1161 laboratory strain, a leu-, Rif R , restriction-
modification defective PAO1 derivative, described as the host of IncP-8 plasmid FP2, conferring the resistance to
mercury. Comparison of PAO1161 genome with PAO1-UW sequence revealed lack of an inversion of a large
genome segment between rRNA operons and 100 nucleotide polymorphisms, short insertions and deletions. These
included a change in leuA, resulting in E108K substitution, which caused leucine auxotrophy and a mutation in
rpoB, likely responsible for the rifampicin resistance. Nonsense mutations were detected in PA2735 and PA1939
encoding a DNA methyltransferase and a putative OLD family endonuclease, respectively. Analysis of revertants in
these two genes showed that PA2735 is a component of a restriction-modification system, independent of PA1939.
Moreover, a 12 kb RPG42 prophage and a novel 108 kb PAPI-1 like integrative conjugative element (ICE)
encompassing a mercury resistance operon were identified. The ICEPae1161 was transferred to Pseudomonas putida
cells, where it integrated in the genome and conferred the mercury resistance.
Conclusions: The high-quality P. aeruginosa PAO1161 genome sequence provides a reference for further research
including e.g. investigation of horizontal gene transfer or comparative genomics.
The strain was found to carry ICEPae1161, a functional PAPI-1 family integrative conjugative element, containing loci
conferring mercury resistance, in the past attributed to the FP2 plasmid of IncP-8 incompatibility group. This
indicates that the only known member of IncP-8 is in fact an ICE
Two SnRK2-Interacting Calcium Sensor Isoforms Negatively Regulate SnRK2 Activity by Different Mechanisms
Get PDFSNF1-related protein kinases 2 (SnRK2s) are key signaling elements regulating abscisic acid-dependent plant development and responses to environmental stresses. Our previous data showed that the SnRK2-interacting Calcium Sensor (SCS) inhibits SnRK2 activity. Use of alternative transcription start sites located within the Arabidopsis (Arabidopsis thaliana) AtSCS gene results in two in-frame transcripts and subsequently two proteins, that differ only by the sequence position of the N terminus. We previously described the longer AtSCS-A, and now describe the shorter AtSCS-B and compare the two isoforms. The two isoforms differ substantially in their expression profiles in plant organs and in response to environmental stresses, in their calcium binding properties, and in their conformational dynamics in the presence and absence of Ca2+ Only AtSCS-A has the features of a calcium sensor. Both forms inhibit SnRK2 activity, but while AtSCS-A requires calcium for inhibition, AtSCS-B does not. Analysis of Arabidopsis plants stably expressing 35S::AtSCS-A-c-myc or 35S::AtSCS-B-c-myc in the scs-1 knockout mutant background revealed that, in planta, both forms are negative regulators of abscisic acid-induced SnRK2 activity and regulate plant resistance against water deficit. Moreover, the data highlight biochemical, biophysical, and functional properties of EF-hand-like motifs in plant proteins
Lactococcus Ceduovirus Phages Isolated from Industrial Dairy Plants—From Physiological to Genomic Analyses
Get PDFLactococcus Ceduovirus (formerly c2virus) bacteriophages are among the three most prevalent phage types reported in dairy environments. Phages from this group conduct a strictly lytic lifestyle and cause substantial losses during milk fermentation processes, by infecting lactococcal host starter strains. Despite their deleterious activity, there are limited research data concerning Ceduovirus phages. To advance our knowledge on this specific phage group, we sequenced and performed a comparative analysis of 10 new Lactococcus lactis Ceduovirus phages isolated from distinct dairy environments. Host range studies allowed us to distinguish the differential patterns of infection of L. lactis cells for each phage, and revealed a broad host spectrum for most of them. We showed that 40% of the studied Ceduovirus phages can infect both cremoris and lactis strains. A preference to lyse strains with the C-type cell wall polysaccharide genotype was observed. Phage whole-genome sequencing revealed an average nucleotide identity above 80%, with distinct regions of divergence mapped to several locations. The comparative approach for analyzing genomic data and the phage lytic spectrum suggested that the amino acid sequence of the orf8-encoded putative tape measure protein correlates with host range. Phylogenetic studies revealed separation of the sequenced phages into two subgroups. Finally, we identified three types of phage origin of replication regions, and showed they are able to support plasmid replication without additional phage proteins
SWI/SNF chromatin remodeling complex and glucose metabolism are deregulated in advanced bladder cancer
Get PDFBladder cancer (BC) is a frequently diagnosed malignancy affecting predomi�nantly adult and elderly populations. It is expected that due to the longer life time,
BC will become even more frequent in the future; thus in consequence, it will rep�resent serious health problem of older society part. The treatment of advanced BC
is mostly ineffective due to its very aggressive behavior. So far, no effective
targeted therapy is used for BC treatment. Here, we found that BC is characterized
by lower protein levels of BRM, INI1, and BAF155 main subunits of SWI/SNF
chromatin remodeling complex (CRC) which is involved in global control of gene
expression and influences various important cellular processes like: cell cycle con�trol, apoptosis, DNA repair, etc. Moreover, the expression of SMARCA2, a BRM
encoding gene, strongly correlated with BC metastasis and expression of such
metabolic genes as PKM2 and PRKAA1. Furthermore, the analysis of T24 and
5637 commonly used BC cell lines revealed different expression levels of meta�bolic genes including FBP1 gene encoding Frutose-1,6-Bisphosphatase, an enzyme
controlling glycolysis flux and gluconeogenesis. The tested BC cell lines exhibited
various molecular and metabolic alterations as well as differential glucose uptake,
growth rate, and migration potential. We have shown that BRM subunit is
involved in the transcriptional control of genes encoding metabolic enzymes.
Moreover, we found that the FBP1 expression level and the SWI/SNF CRCs may
serve as markers of molecular subtypes of BC. Collectively, this study may provide
a new knowledge about the molecular and metabolic BC subtypes which likely
will be of high importance for the clinic in the future
Recombination and Pol ζ Rescue Defective DNA Replication upon Impaired CMG Helicase—Pol ε Interaction
Get PDFThe CMG complex (Cdc45, Mcm2–7, GINS (Psf1, 2, 3, and Sld5)) is crucial for both DNA replication initiation and fork progression. The CMG helicase interaction with the leading strand DNA polymerase epsilon (Pol ε) is essential for the preferential loading of Pol ε onto the leading strand,
the stimulation of the polymerase, and the modulation of helicase activity. Here, we analyze the consequences of impaired interaction between Pol ε and GINS in Saccharomyces cerevisiae cells with the psf1-100 mutation. This significantly affects DNA replication activity measured in vitro, while in vivo, the psf1-100 mutation reduces replication fidelity by increasing slippage of Pol ε, which manifests as an elevated number of frameshifts. It also increases the occurrence of single-strandedDNA(ssDNA) gaps
and the demand for homologous recombination. The psf1-100 mutant shows elevated recombination rates and synthetic lethality with rad52D. Additionally, we observe increased participation of DNA polymerase zeta (Pol ζ) in DNA synthesis. We conclude that the impaired interaction between
GINS and Pol ε requires enhanced involvement of error-prone Pol ζ, and increased participation of recombination as a rescue mechanism for recovery of impaired replication forks
TMAO, a seafood-derived molecule, produces diuresis and reduces mortality in heart failure rats
Get PDFAntarctic fur seal (Arctocephalus gazella) annual migration and temporal patterns of on-shore occurrence of leucistic individuals on King George Island.
Get PDFNon-invasive tracking the on-shore occurrence of the atypically pigmented animals and determination of land residency duration of leucistic seals would help us find out more about the rotation of the migrating population. During seven austral summer seasons (2011–2018), by counting the animals every 10 days at the Cape Lions Rump shore, King George Island, South Shetlands, in the Antarctic Specially Protected Area No. 151 and the adjacent ice-free land (31.52 km2) we registered fourteen leucistic individuals per a total of 43,919 animals. Moreover, daily monitoring of local fauna resulted in further 33 leucistic animals (together 47, in all seasons). Whilst the results of 10-day censuses of the total population were similar inter-seasonally, a tendency for increased occurrence of leucistic individuals in successive seasons was revealed. Generally, the number of animals increased significantly as season progressed. Since leucistic individuals stayed on-shore for 1–2 days usually, it can be hypothesised that the observation of migrating Antarctic fur seals every 3 days does not involve the same individuals. Also, additional every 5-day censuses taken in one season in ASPA 151 resulted in a higher seasonal number of animals, which proves that more frequent counts help us estimate population abundance more efficiently. Thus, every 5-day counts are proposed as a feasible and justified method of population monitoring