Effect of S-methylmethionine as a protective compound on the metabolism of agricultural plants at low temperature

The present research dealt primarily with a special protective mechanism which appears to be part of the defence responses of plants to low temperature. It was found that the metabolisation of S-methylmethionine (SMM) had a stimulatory effect on polyamine biosynthesis. The results proved that SMM acted via a special metabolic pathway to increase the quantities of certain polyamines (putrescine, agmatine, spermidine) known to be involved in the stabilisation of the cell environment, the macromolecules and the cell membranes. It was demonstrated that in wheat varieties, peas and maize, SMM treatment was able, to varying extents, to reduce low temperature-induced electrolyte leakage measured in terms of electrical conductivity

Studies on Tissue Protective Cytokines in Remyelination and Regenerative Medicine

There is growing interest in the tissue-protective effects of some cytokines, including erythropoietin (EPO) and the IL-6 family cytokine leukaemia inhibitory factor (LIF); both have receptors, and exert their effects, on cells other than their primary targets. In the nervous system, these cytokines could aid in the treatment of demyelinating diseases, such as multiple sclerosis, by protecting myelin from damage and supporting remyelination after damage has occurred. Previous work has shown that EPO increases myelination in oligodendrocytes, the cells responsible for myelin deposition in the central nervous system. I aimed to determine if LIF shares the promyelinating effects of EPO and understand more about the mechanisms mediating tissue-protective cytokine-induced myelination. A model of rat oligodendrocyte precursor cells was used and their myelinating capacity was measured as represented by myelin oligodendrocyte glycoprotein (Mog) expression. Initially I studied EPO and LIF’s effects on these cells before defining the molecular mechanisms causing their effects using microarray gene expression analysis. EPO increased myelination by eight-fold, a level that was sustained at concentrations up to and including 400ng/ml. After treatment with LIF at 0.2ng/ml Mog expression was increased by two-fold, but concentrations above 2ng/ml caused a reduced expression of Mog. Interestingly, when LIF and EPO were added simultaneously there was a significant reduction in EPO-induced Mog expression suggesting that LIF induced an inhibitory feedback that was responsible for blocking not only its own, but also EPO’s effect. The inhibitory feedback was replicated when LIF was replaced by ciliary neurotrophic factor (CNTF) and oncostatin M (OSM), glycoprotein 130 (GP130) cytokines that use the same receptor as LIF. The signalling mechanisms that may have caused the inhibition of EPO-induced Mog were then investigated. Socs3, a known inhibitory feedback of LIF and other IL-6 cytokines, negatively correlated with Mog expression, as the higher concentration of LIF and the simultaneous EPO and LIF treatment induced the greatest Socs3 expression. Gene expression microarray analysis was performed to elucidate further mechanisms that may cause the inhibition of EPO-induced Mog. A variety of candidate genes were identified and their expression validated by qPCR. The roles of Tlr2/Myd88 and lipocalin 2 were investigated further and Tlr2 activation showed a functional effect on Mog expression. The results showed that LIF and other GP130 cytokines inhibited EPO’s positive effect on myelination and clarified some of the mechanisms that resulted in inhibition. The implications of my work could be an increase in efficacy of EPO treatment, as the work has elucidated mechanisms that could inhibit EPO’s promyelinating effect. Increased efficacy of EPO would impact new therapies and therapeutic approaches using tissue protective cytokines in regenerative medicine

Structural and functional characterization of R1-homologous genes

The major disease for Solanum tuberosum is the foliage and tuber blight caused by the oomycete Phytophthora infestans. Defeat of this pathogen is often connected with the application of pesticides, which are toxic and increase production costs. However plants dispose over a class of genes which are able to mediate resistance to existing pathogens known as R-genes. These genes play a key-role in effector-induced resistance responses which finally result in a form of programmed cell death (PCD), the hypersensitive response (HR). R1 belongs to a major class of resistance genes (NBS-LRR class genes) and is known to mediate race-specific resistance to P. infestans. The chromosomal region around R1 has been sequenced and revealed eight open reading frames (ORFs) with high homology to R1. These genes are part of a cluster of resistance genes on S. tuberosum chromosome V. The nine ORFs share higher sequence similarity with each other than with any other resistance gene in S. tuberosum known so far and are therefore considered as the R1-family. Within this project the molecular characterization of the R1-family and the response genes was performed. The major goal of this study was the molecular characterization of the R1-mediated resistance phenotype. To achieve this, a complex comparative transcriptome analysis of transgenic plants was performed in the initial stages of late blight infection. Different Desirée lines either with or without the R1-gene were used in this study. In addition, transformants with the R1-homologous gene ORF45, which shares high homology to R1 but does not confer resistance was analyzed. To generate the highest possible output rate, one of the new Next Generation Sequencing methods was used in combination with the DeepSAGE-technology. Performance parameters were validated. Various data analysis techniques were evaluated and at the end a pipeline was composed, which was able to process the data and leads to a state-of-the-art statistical data assessment. The data analysis was able to provide further evidence for an intensive role of plant hormone signalling during the early stages of infection. Moreover in these key-processes different expression behaviors were observed in the incompatible versus the compatible interaction. In addition it was possible to give experimental evidence for the expression of five of the members of the R1-family and cytosolic resistance mechanism in Solanum nigrum which is able to sense the presence of effector molecules from Phytophthora infestans

Online voluntary mentoring: Optimising the assignment of students and mentors

After the closure of the schools in Hungary from March 2020 due to the pandemic, many students were left at home with no or not enough parental help for studying, and in the meantime some people had more free time and willingness to help others in need during the lockdown. In this paper we describe the optimisation aspects of a joint NGO project for allocating voluntary mentors to students using a web-based coordination mechanism. The goal of the project has been to form optimal pairs and study groups by taking into the preferences and the constraints of the participants. In this paper we present the optimisation concept, and the integer programming techniques used for solving the allocation problems. Furthermore, we conducted computation simulations on real and generated data for evaluate the performance of this dynamic matching scheme under different parameter settings

Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to antimicrobial drugs. The aim of this study was to determine and compare the in vitro susceptibility of planktonic cells and biofilms of M. pachydermatis isolates to ketoconazole and itraconazole. The presence of biofilm formation was confirmed by crystal violet staining and absorbance measurement at 595 nm wavelength, and by a scanning electron microscopy method. Cell viability was determined by the Celltiter 96 Aqueous One solution assay containing a water-soluble tetrazolium compound (MTS) with absorbance measurement at 490 nm. Planktonic cell minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of ketoconazole and itraconazole were very low: MIC90 and MFC90 were 0.032 and 0.125 μg/ml for ketoconazole, while 0.063 and 0.25 μg/ml for itraconazole, respectively. Also, the half maximal effective concentrations (EC50) of itraconazole were higher for planktonic cells and biofilms compared to ketoconazole. The EC50 values of ketoconazole were 18–169 times higher and those of itraconazole 13–124 times higher for biofilms than for planktonic cells. Biofilm EC50 levels exceeded MICs 103–2060 times for ketoconazole and 84–1400 times for itraconazole. No significant difference was found between these values of the two substances. In conclusion, biofilms of all examined M. pachydermatis strains were much less susceptible to ketoconazole and itraconazole than their planktonic forms

Online puzzle játék

A program egy ASP.NET és Angular technológiákkal készült webalkalmazás, amely képeket vág fel puzzle-é és a felhasználó ki tudja rakni, vezet továbbá statisztikákat a korábbi játékokról

Online voluntary mentoring: Optimising the assignment of students and mentors

After the closure of the schools in Hungary from March 2020 due to the pandemic, many students were left at home with no or not enough parental help for studying, and in the meantime some people had more free time and willingness to help others in need during the lockdown. In this paper we describe the optimisation aspects of a joint NGO project for allocating voluntary mentors to students using a webbased coordination mechanism. The goal of the project has been to form optimal pairs and study groups by taking into account the preferences and the constraints of the participants. In this paper, we present the optimisation concept and the integer programming techniques used for solving the allocation problems. Furthermore, we conducted computational simulations on real and generated data to evaluate the performance of this dynamic matching scheme under different parameter settings