ATM/ATR-dependent Tyr15 phosphorylation of cyclin-dependent kinases in response to hydroxyurea in Vicia faba root meristem cells

DNA damage or stalled replication forks activate cell cycle checkpoints. However, the regulation of metabolic pathways that are responsible for maintenance of genome integrity in plants is still largely unknown. Present research on Vicia faba root meristem cells indicates that inhibitory phosphorylation of cyclin-dependent kinases (Cdks) at Tyr15 plays a prominent role during blockage of cell cycle in response to genotoxic stress. Phosphorylation of P-loop in Cdks takes place in ATM/ATR-dependent manner. Although, Tyr15 phosphorylation upon hydroxyurea (HU) treatment was found in most cells classified to G1 and S phase, interestingly, the number of phoshpo-Tyr15-positive cells decreases in G2 phase. Presented data confirm much similarity in regulation of Cdks functions under genotoxic stress between plants and animals; however, they may also substantiate evolutionarily developed differences especially in regulation of G2/M transition between these two kingdoms

O Państwowej Radzie Ochrony Środowiska (PROŚ) i przyszłości czasopisma „Problemy Ekorozwoju”

We strongly believe that the journal is highly required on domestic as well as international markets of scientific publications in a dynamically developing area of sustainable development, which is so far mostly exploit for political reasons than for a real creation of better living conditions of tomorrow and after-tomorrow.Jesteśmy głęboko przekonani, że czasopismo jest niezwykle potrzebne, tak na krajowym, jak też międzynarodowym rynku publikacji naukowych, w dynamicznie rozwijającym się obszarze zagadnień zrównoważonego rozwoju, które są, jak dotąd, wykorzystywane bardziej do celów politycznych, niż do rzeczywistej poprawy warunków życia jutro i pojutrze

Overview of Polish botanical studies in the Eastern Carpathians and the role of the Bieszczady National Park in protecting plant diversity

Polish scientific studies on the flora and vegetation of Eastern Carpathians started about 150 years ago. Researches were focused on the northern part of the range. Results of studies made until 1939 created good basis of botanical knowledge. After Word War II and political changes only a small part of Eastern Carpathian was left in Poland, namely the Western Bieszczady Mts. Detailed studies of these mountains resulted in foundation in 1973 of the Bieszczady National Park, which main object was to protect very interesting and particular vegetation cover together with rich forest fauna, especially of large mammals. Now Bieszczady National Park is a unique place in Poland where rich flora and vegetation with Eastern Carpathian elements is protected

A New Policy Iteration Algorithm For Reinforcement Learning in Zero-Sum Markov Games

Optimal policies in standard MDPs can be obtained using either value iteration or policy iteration. However, in the case of zero-sum Markov games, there is no efficient policy iteration algorithm; e.g., it has been shown that one has to solve Omega(1/(1-alpha)) MDPs, where alpha is the discount factor, to implement the only known convergent version of policy iteration. Another algorithm, called naive policy iteration, is easy to implement but is only provably convergent under very restrictive assumptions. Prior attempts to fix naive policy iteration algorithm have several limitations. Here, we show that a simple variant of naive policy iteration for games converges exponentially fast. The only addition we propose to naive policy iteration is the use of lookahead policies, which are anyway used in practical algorithms. We further show that lookahead can be implemented efficiently in the function approximation setting of linear Markov games, which are the counterpart of the much-studied linear MDPs. We illustrate the application of our algorithm by providing bounds for policy-based RL (reinforcement learning) algorithms. We extend the results to the function approximation setting.Comment: 41 page

Mobilność subdyscyplinarna a zmiany na globalnym rynku pracy

The aim of this article is to present a proposal leading to the modification of the concept of vocational education. Its main feature is the consolidation of several disciplines, especially sub-disciplines, which could result in greater mobility of graduates on the labour market. This requires the modification of many occupations and employment structure.Celem niniejszego artykułu jest przedstawienie propozycji prowadzącej do zmodyfikowania koncepcji kształcenia zawodowego. Jej główną cechą jest scalanie kilku dyscyplin, a szczególnie subdyscyplin, co mogłoby spowodować większą mobilność absolwentów na rynku pracy. Wymaga to modyfikacji wielu zawodów i struktury zatrudnienia

Increased transcription in hydroxyurea-treated root meristem cells of Vicia faba

Hydroxyurea (HU), an inhibitor of ribonucleotide reductase, prevents cells from progressing through S phase by depletion of deoxyribonucleoside triphosphates. Concurrently, disruption of DNA replication leads to double-strand DNA breaks. In root meristems of Vicia faba, HU triggers cell cycle arrest (preferentially in G1/S phase) and changes an overall metabolism by global activation of transcription both in the nucleoplasmic and nucleolar regions. High level of transcription is accompanied by an increase in the content of RNA polymerase II large subunit (POLR2A). Changes in transcription activation and POLR2A content correlate with posttranslational modifications of histones that play a role in opening up chromatin for transcription. Increase in the level of H4 Lys5 acetylation indicates that global activation of transcription following HU treatment depends on histone modifications