Nitric oxide as a potent signalling molecule in plants

The role of NO in stress responses in plants came in the focus of plant science in the last decade. Better understanding of plant stress responses is very important in the light of increasing intensities of stressors like drought, salinity and others, due to global climatic and environmental changes. Our knowledge, concerning signal transduction pathways is very scarce, especially in terms of NO-related alterations in proteins and gene expression as well as regulation. In this review we consider different NO-reactions, signalling pathways, NO – plant hormone interactions and NO-induced and -mediated signalization under osmotic stress in relation with the development of root architecture

Nitric oxide production induced by heavy metals in Brassica juncea L. Czern. and Pisum sativum L.

In plants, nitric oxide (NO) has multiple roles in defence reactions under abiotic stresses, including heavy metal load. Literature data suggest that there is a causal relationship between NO and iron metabolism but the effects of essential micronutrients/toxic heavy metals on NO production have not been investigated. In this study our aim is to demonstrate the possible role of NO in the plant response to heavy metals in the metal accumulator Brassica juncea and the crop plant Pisum sativum grown in the presence of either 100 μM cadmium, copper or zinc. NO production was measured in the root tips with fluorescent method, using 4,5-diaminofluorescein diacetate (DAF-2 DA), a specific dye to nitric oxide. We obtained different NO levels with the different heavy metal load: the most effective metal were copper and cadmium, in this case the NO production became double after one week treatment. In case of copper load, two-phase kinetics was found: a fast NO burst in the first six hours was followed by a slower, gradual increase. The fast appearance of NO in the presence of cupric ions suggest that it can be a novel reaction hitherto not studied in plants under heavy metal stress. After long-term treatment, NO levels were inversely related to the nitrite concentrations originated from nitrate reductase activity suggesting the conversion of nitrite to nitric oxide by the known enzymatic ways

Generation of nitric oxide in roots of Pisum sativum, Triticum aestivum and Petroselinum crispum plants under osmotic and drought stress

The concentration-, time- and tissue-dependent generation of nitric oxide (NO) was investigated in roots of Pisum sativum L. and Triticum aestivum L.. under osmotic stress, as well as in Petroselinum crispum L. under drought stress. Osmotic stress for pea and wheat was induced by polyethylene glycol (PEG) treatments in nutrient solution, while drought stress was caused by withdrawal of watering of soil-grown parsley. NO was detected by the NO-specific fluorescent dye, 4,5-diaminofluorescein-diacetate (DAF-2DA), using Zeiss Axiowert 200 M type fluorescent microscope. Changes in nitrate reductase activity was determined in the same series of treatments. Our results show that NO generation was proportional to the osmotic concentration of PEG both in pea and wheat roots and to the severity of drought in parsley root. The sites of NO production were in the regions of meristemic and elongation zones, and in case of wheat, root cap was also involved. In parsley root, the exodermis and the central cylinder showed the most intensive NO accumulation. In wheat and pea, time course revealed a fast transient (several hours) and a slow permanent increase in NO production. It is suggested that the fast kinetics may be due to non-enzymatic, while the constant increase was caused by enzymatic reactions. In parsley, long term experiments were carried out including the regeneration process after rewatering. It is concluded that NO plays a role as signaling molecule under osmotic and drought stress conditions

Early nitric oxide (NO) responses to osmotic stress in pea, Arabidopsis and wheat

Nitric oxide (NO) is a novel diffusible, lipophylic gas, which acts in diverse physiological processes in plants. The 4,5-diaminofluorescein diacetate (DAF-2DA)- based in vivo and in situ fluorescence method of NO detection gives an excellent opportunity to investigate the transient NO generations in plant tissues. During our work with the help of this method time-dependent kinetics of NO formation were investigated in osmotic stress treated-Pisum sativum L., Triticum aestivum L. and Arabidopsis thaliana L. roots. Osmotic stress was provoked by addition polyethylene glycol (PEG 6000) to the nutrient solution. In the case of pea plants an early phase of NO generation was distinguishable, which reached a maximum point at 24th hours after PEG treatment. This transient NO accumulation was followed by a slower but more significant NO formation. In Arabidopsis roots NO was formed already in the first 12 hours, the highest NO level was detected only 36 hours after treatment. Interestingly, in PEG-treated wheat roots the first NO peak appeared already after 1 hour treatment, which slightly moderated in the following 12 hours. In the cases of all the investigated plant species two phased NO generation was observed. The significant transient NO bursts were followed by slower NO accumulations. These early NO formations could have an important role in acclimation of plants to osmotic stress

A nitrogén-monoxid jelmolekulával foglalkozó kutatások múltja, jelene és jövője a Szegedi Tudományegyetem Növénybiológiai Tanszékén

A nitrogén-monoxid (NO) hatásainak tanulmányozása 2004-ben kezdődött meg az SZTE Növénybiológiai Tanszékén, hat évvel a mérföldkőnek számító felfedezése után. Az ekkor rendkívül nagy érdeklődésre számot tartó nemzetközi kutatási irányvonalba illeszkedtünk be azáltal, hogy stressz- és hormonkezelés hatására vizsgáltuk a NO képződését és szerepét a gyökérfejlődésben, valamint valószínűsítettük a nitrát reduktáz enzim szerepét a gyökér NO termelésében. Az „SZTE Nitrogén-monoxid Jelátviteli Kutatócsoport” megalakulását követően, megtartva a kezdeti kutatási irányvonalat, növényi hormonok (auxin, citokinin, etilén, strigolakton) és a NO jelmolekula kapcsolatát jellemeztük a gyökérfejlődési folyamatok során. Később nehézfémek- és nem fémes elemek többlete által kiváltott stresszfolyamatokat tanulmányoztunk, majd elkezdtünk a NO mellett egyéb molekulákat, az ún. reaktív nitrogénformákat (RNF) is vizsgálni, és a kutatócsoportunk nevét „SZTE Reaktív Nitrogénforma Jelátviteli Kutatócsoport”-ra változtattuk. A stresszhatásra megváltozott RNF metabolizmus és jelátvitel stresszt enyhítő hatását, valamint az RNF túlprodukciója nyomán kialakuló nitro-oxidatív stresszt tanulmányoztuk részletesen. Majd nyitva az új irányvonalak felé, négy évvel ezelőtt, az SZTE vegyészeivel együttműködésben elkezdtük tanulmányozni a nanoanyagok által kiváltott nitro-oxidatív folyamatokat. Legújabb kutatásaink pedig egy mezőgazdasági problémára, a növényi cinkhiányra összpontosítanak. Az elmúlt 18, NO/RNF kutatással töltött esztendőben igyekeztünk a nemzetközi kutatási irányvonalakat követve újabb és újabb aspektusokból megismerni ezt az érdekes, multifunkciós molekulacsaládot, ami a kutatási háttérproblémák változtatásával valósult meg, a NO/RNF molekulákat fókuszban tartva. A sikeres kutatómunkához elengedhetetlennek tartjuk a kiépített hazai és nemzetközi kutatási együttműködéseinket, melyek fenntartása és további építése a jövőben is feladatunk

Hagyomány és modernitás a "Visegrádi négyek" családjainak életmódjában ; Táplálkozási szokások

Our study gives an overview of the theoretical and research methodological concepts of the international empirical research called „Tradition and Modernity in the life-style of the families of the Visegrád countries”. Our main hypothesis is, that in the Visegrád Countries (Hungary, Poland, Czech Republic and Slovakia), and in the „city and its surroundings”, as opposed to the main sociological theories (Giddens), the role of traditional values and behaviour is still important. In the framework of the present study we verify our hypothesis on the hasis of international data selected from the domain of nutrition from among the researched domains of life-style

LADA type diabetes, celiac diasease, cerebellar ataxia and stiff person syndrome. A rare association of autoimmune disorders.

Celiac disease--in its typical form--is a chronic immune-mediated enteropathy with typical clinical symptoms that develops against gliadin content of cereal grains, and is often associated with other autoimmune diseases. In cases of atypical manifestation classic symptoms may be absent or mild, and extra-intestinal symptoms or associated syndromes dominate clinical picture. The authors present a longitudinal follow-up of such a case. A 63-years old woman was diagnosed with epilepsy at the age of 19, and with progressive limb ataxia at the age of 36, which was initially thought to be caused by cerebellar atrophy, later probably by stiff person syndrome. At the age 59, her diabetes mellitus manifested with type 2 diabetic phenotype, but based on GAD positivity later was reclassified as type 1 diabetes. Only the last check-up discovered the celiac disease, retrospectively explaining the entire disease course and neurological symptoms. By presenting this case, the authors would like to draw attention to the fact that one should think of the possibility of celiac disease when cerebellar ataxia, progressive neurological symptoms and diabetes are present at the same time. An early diagnosis may help to delay the progression of disease and help better treatment

Excision efficiency is not strongly coupled to transgenic rate: cell type dependent transposition efficiency of Sleeping Beauty and piggyBac DNA transposons

The Sleeping Beauty (SB) and piggyBac (PB) DNA transposons represent an emerging new gene delivery technology, potentially suitable for human gene therapy applications. Previous studies pointed to important differences between these transposon systems, depending on the cell types examined and the methodologies applied. However, efficiencies cannot always be compared because of differences in applications. In addition, “overproduction inhibition,” a phenomenon believed to be a characteristic of DNA transposons, can remarkably reduce the overall transgenic rate, emphasizing the importance of transposase dose applied. Therefore, because of lack of comprehensive analysis, researchers are forced to optimize the technology for their own “in-house” platforms. In this study, we investigated the transposition of several SB (SB11, SB32, SB100X) and PB (mPB and hyPB) variants in various cell types at three levels: comparing the excision efficiency of the reaction by real-time PCR, testing the overall transgenic rate by detecting cells with stable integrations, and determining the average copy number when using different transposon systems and conditions. We concluded that high excision activity is not always followed by a higher transgenic rate, as exemplified by the hyperactive transposases, indicating that the excision and the integration steps of transposition are not strongly coupled as previously thought. In general, all levels of transposition show remarkable differences depending on the transposase used and cell lines examined, being the least efficient in human embryonic stem cells (hESCs). In spite of the comparably low activity in those special cell types, the hyperactive SB100X and hyPB systems could be used in hESCs with similar transgenic efficiency and with reasonably low (2–3) transgene copy numbers, indicating their potential applicability for gene therapy purposes in the future