O mediewistycznej twórczości Juliusza Bardacha

O mediewistycznej twórczości Juliusza Bardach

New Urea Derivatives Are Effective Anti-senescence Compounds Acting Most Likely via a Cytokinin-Independent Mechanism

Stress-induced senescence is a global agro-economic problem. Cytokinins are considered to be key plant anti-senescence hormones, but despite this practical function their use in agriculture is limited because cytokinins also inhibit root growth and development. We explored new cytokinin analogs by synthesizing a series of 1,2,3-thiadiazol-5-yl urea derivatives. The most potent compound, 1-(2-methoxy-ethyl)-3-1,2,3-thiadiazol-5-yl urea (ASES - Anti-Senescence Substance), strongly inhibited dark-induced senescence in leaves of wheat (Triticum aestivum L.) and Arabidopsis thaliana. The inhibitory effect of ASES on wheat leaf senescence was, to the best of our knowledge, the strongest of any known natural or synthetic compound. In vivo, ASES also improved the salt tolerance of young wheat plants. Interestingly, ASES did not affect root development of wheat and Arabidopsis, and molecular and classical cytokinin bioassays demonstrated that ASES exhibits very low cytokinin activity. A proteomic analysis of the ASES-treated leaves further revealed that the senescence-induced degradation of photosystem II had been very effectively blocked. Taken together, our results including data from cytokinin content analysis demonstrate that ASES delays leaf senescence by mechanism(s) different from those of cytokinins and, more effectively. No such substance has yet been described in the literature, which makes ASES an interesting tool for research of photosynthesis regulation. Its simple synthesis and high efficiency predetermine ASES to become also a potent plant stress protectant in biotechnology and agricultural industries

Policy Recommendations to Improve Mental Health in Polish Prisons

Context: Mental health is a central aspect of public health and social development, as such it corresponds to target 3.4 of the Sustainable Development Goals. This target aims to promote mental health and well-being, making it especially necessary to address this matter in environments such as prisons where exposure to risk factors is high. Incarceration itself is a cause of mental illness. Central and Eastern European countries hold some of the highest prison populations in the region and Poland numbers in this regard are 50% higher than the average in the European Union (EU) (about 179 inmates per 100,000 inhabitants). In Polish prisons, the chance of receiving adequate psychiatric and psychological care is limited due to a shortage of trained personnel and scarce infrastructure. However, data on mental health in Polish prisons is not routinely reported from official sources. Article 150 of the Polish Penal Code attempts to protect the mental health of inmates; yet, in reality, there is no legal enforcement to apply these measures, a feature shared with most of its neighbouring countries. The aim of this policy brief is to offer recommendations to lower recidivism rates, up-scale prison staff and create spill-over effects on (mental) healthcare and security in Polish prisons.Policy Options: The World Health Organization (WHO) European Framework for Action on Mental Health 2021-2025 should be adapted to the Polish Prison System. Best practices focus on a collaborative approach centred on healthcare services, labour policies, well-being and rehabilitation. Ideally, incarceration provides inmates with the possibility to be included and active, to see their relatives, to vote, to be engaged and maintain contact with the outside society. These best practices statistically reduce mental illnesses, lower recidivism and promote inclusion and rehabilitation. Recommendations: To tackle mental health challenges that prisoners in Poland experience, it is recommended to adapt a new approach with the following components: improving methodological quality of data collection as well as routine reporting to enable good governance structures, promoting collaborative efforts among stakeholders, and strengthening existing resources through capacity building which has been convincingly demonstrated as the most cost-effective type of interventions

Materiały do polskiej bibliografii historycznoprawnej za rok 2010. Pod redakcją Andrzeja B. Zakrzewskiego

Materiały do polskiej bibliografii historycznoprawnej za rok 2010. Pod redakcją Andrzeja B. Zakrzewskieg

The cyanobacterial protoporphyrinogen oxidase HemJ is a new b-type heme protein functionally coupled with coproporphyrinogen III oxidase

Protoporphyrinogen IX oxidase (PPO), the last enzyme that is common to both chlorophyll and heme biosynthesis pathways, catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX. PPO has several isoforms, including the oxygen-dependent HemY and an oxygen-independent enzyme, HemG. However, most cyanobacteria encode HemJ, the least characterized PPO form. We have characterized HemJ from the cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803) as a bona fide PPO; HemJ down-regulation resulted in accumulation of tetrapyrrole precursors and in the depletion of chlorophyll precursors. The expression of FLAG-tagged Synechocystis 6803 HemJ protein (HemJ.f) and affinity isolation of HemJ.f under native conditions revealed that it binds heme b. The most stable HemJ.f form was a dimer, and higher oligomeric forms were also observed. Using both oxygen and artificial electron acceptors, we detected no enzymatic activity with the purified HemJ.f, consistent with the hypothesis that the enzymatic mechanism for HemJ is distinct from those of other PPO isoforms. The heme absorption spectra and distant HemJ homology to several membrane oxidases indicated that the heme in HemJ is redox-active and involved in electron transfer. HemJ was conditionally complemented by another PPO, HemG from Escherichia coli. If grown photoautotrophically, the complemented strain accumulated tripropionic tetrapyrrole harderoporphyrin, suggesting a defect in enzymatic conversion of coproporphyrinogen III to protoporphyrinogen IX, catalyzed by coproporphyrinogen III oxidase (CPO). This observation supports the hypothesis that HemJ is functionally coupled with CPO and that this coupling is disrupted after replacement of HemJ by HemG

Porphyrin Binding to Gun4 protein, Facilitated by a Flexible Loop, Controls Metabolite Flow through the Chlorophyll Biosynthetic Pathway

In oxygenic phototrophs, chlorophylls, hemes and bilins are synthesized by a common branched pathway. Given the phototoxic nature of tetrapyrroles, this pathway must be tightly regulated and an important regulatory role is attributed to Mgchelatase enzyme at the branching between the heme and chlorophyll pathway. Gun4 is a porphyrin-binding protein known to stimulate in vitro the Mg-chelatase activity but how the Gun4-porphyrin complex acts in the cell was unknown. To address this issue we first performed simulations to determine the porphyrin-docking mechanism to the cyanobacterial Gun4 structure. After correcting crystallographic loop contacts, we determined the binding site for Mgprotoporphyrin IX. It revealed that the orientation of 6/7 loop is critical for the binding and the magnesium ion held within the porphyrin is coordinated by Asn211 residue. We also identified the basis for stronger binding in the Gun4-1 variant and for weaker binding in the W192A mutant. The W192A-Gun4 was further characterized in Mg-chelatase assay showing that tight porphyrin-binding in Gun4 facilitates its interaction with the Mg-chelatase ChlH subunit. Finally, we introduced the W192A mutation into Synechocystis 6803 cells and show that the Gun4-porphyrin complex is important for the accumulation of ChlH and for channeling metabolites into the chlorophyll biosynthetic pathway.This work was supported by project P501/12/G055 of the Czech Science Foundation, and by the National Programme of Sustainability I (LO1416) and by ERC 2009-Adg25027-PELE (to V.G). J.K. was supported by project Algain (EE2.3.30.0059). N.B.P.A., P.A.D., A.A.B. and C.N.H. thank the Biotechnology and Biological Sciences Research Council (BBSRC) U.K. for funding, under award numbers BB/G021546/1 and BB/M000265/1. CNH was also supported by an Advanced Award 338895 from the European Research Council.Peer ReviewedPostprint (author's final draft

Mutations suppressing the lack of prepilin peptidase provide insights into the maturation of the major Pilin Protein in Cyanobacteria

Type IV pili are bacterial surface-exposed filaments that are built up by small monomers called pilin proteins. Pilins are synthesized as longer precursors (prepilins), the N-terminal signal peptide of which must be removed by the processing protease PilD. A mutant of the cyanobacterium Synechocystis sp. PCC 6803 lacking the PilD protease is not capable of photoautotrophic growth because of the impaired function of Sec translocons. Here, we isolated phototrophic suppressor strains of the original ΔpilD mutant and, by sequencing their genomes, identified secondary mutations in the SigF sigma factor, the γ subunit of RNA polymerase, the signal peptide of major pilin PilA1, and in the pilA1-pilA2 intergenic region. Characterization of suppressor strains suggests that, rather than the total prepilin level in the cell, the presence of non-glycosylated PilA1 prepilin is specifically harmful. We propose that the restricted lateral mobility of the non-glycosylated PilA1 prepilin causes its accumulation in the translocon-rich membrane domains, which attenuates the synthesis of membrane proteins.This work was supported by the Czech Science Foundation (project 19-29225X) and the Institutional Research Concept (RVO: 61388971). TT was supported by the Academy of Finland (265807).Peer ReviewedPostprint (published version

Mutations Suppressing the Lack of Prepilin Peptidase Provide Insights Into the Maturation of the Major Pilin Protein in Cyanobacteria

Type IV pili are bacterial surface-exposed filaments that are built up by small monomers called pilin proteins. Pilins are synthesized as longer precursors (prepilins), the N-terminal signal peptide of which must be removed by the processing protease PilD. A mutant of the cyanobacterium Synechocystis sp. PCC 6803 lacking the PilD protease is not capable of photoautotrophic growth because of the impaired function of Sec translocons. Here, we isolated phototrophic suppressor strains of the original Delta pilD mutant and, by sequencing their genomes, identified secondary mutations in the SigF sigma factor, the gamma subunit of RNA polymerase, the signal peptide of major pilin PilA1, and in the pilA1-pilA2 intergenic region. Characterization of suppressor strains suggests that, rather than the total prepilin level in the cell, the presence of non-glycosylated PilA1 prepilin is specifically harmful. We propose that the restricted lateral mobility of the non-glycosylated PilA1 prepilin causes its accumulation in the translocon-rich membrane domains, which attenuates the synthesis of membrane proteins.</p

V456 Ophiuchi and V490 Cygni: Systems with the shortest apsidal-motion periods

Our main aim is the first detailed analysis of the two eclipsing binaries V456 Oph and V490 Cyg. The system V456 Oph has been studied both photometrically via an analysis of its light curve observed by the INTEGRAL/OMC and by the period analysis of all available times of minima. V490 Cyg has been studied by means of a period analysis only. Many new times of minima for both systems have recently been observed and derived. This allows us for the first time to study in detail the processes that affect both binaries. The main result is the discovery that both systems have eccentric orbits. For V456 Oph we deal with the eccentric eclipsing binary system with the shortest orbital period known (about 1.016 day), while the apsidal motion period is about 23 years. V490 Cyg represents the eclipsing system with the shortest apsidal motion period (about 18.8 years only). The two components of V456 Oph are probably of spectral type F. We compare and discuss the V456 Oph results from the light curve and the period analysis, but a more detailed spectroscopy is needed to confirm the physical parameters of the components more precisely.Comment: 4 pages, 3 figures, published in A&A: 2011A&A...527A..43