A nemi hormonok és neuroszteroidok neuroprotektív szerepe: in vivo és in vitro vizsgálatok = Neuroprotective effects of gonadal hormones and neurosteroids: in vivo and in vitro studies

A jelen pályázat keretében elvégzett vizsgálatok célja azon sejt és molekuláris szintű mechanizmusok tanulmányozása volt, melyek az öregedésből ill. az agyi sérülésekből adódó morfológiai és funkcionális károsodások enyhítését lehetővé teszik. Különböző állatmodelleken a női nemi hormon (ösztrogén) ill. az egyik neuroszteroid, dehydroepiandoszteron (DHEA) hatását tanulmányoztuk az idegi sérüléseket követő reakciókra. Legfontosabb megállapításaink: A patkány szaglógumó kísérletes deafferentációját követően kialakuló reaktív asztrogliózist az ösztrogén és a DHEA egyaránt csökkenti. Aromatáz gátló fadrozol segítségével igazoltuk, hogy a protektív hatás kialakulásáért nem maga a neuroszteroid, hanem az abból lokálisan szintetizálódó 17β-ösztadiol a felelős. Patkány agykéregben hideg lézióval előidézett sérülés mértékét dehydroepiandoszteron szulfát (DHEAS) kezelésével csökkenteni lehet. Figyelemreméltó, hogy ilyen körülmények között a neuroszteroid protektív hatása kifejezettebb, ha azt a sérülést követően alkalmazzuk. BrdU-val történő jelöléssel igazoltuk, hogy a patkány szaglógumójában az ösztrogén régió-specifikus módon hat az agyterületen folyó neurogenezisre, az újonnan integrálódó interneuronok túlélésére. | In the present project we studied the process of neurodegeneration occurring during normal ageing or induced by injury. By using different animal models we have studied the effects of estrogen and the neurosteroid dehydroepiandrosterone (DHEA) on the neuronal and glial reactions following neuronal injury. Our aim was to identify those cellular and molecular mechanisms, which were responsible for the neuroprotective effects of these steroids. In deafferentated olfactory bulb of adult rats we have demonstrated that DHEA attenuates the glial reaction to denervation and may regulate glial plasticity in the olfactory glomeruli. With the use of aromatase inhibitor fadrozole we have provided evidences that these effects are likely to be mediated by the local conversion of DHEA to 17 β-estradiol. In a focal cortical cold lesion model we have shown that the size of injury can be decreased by dehydroepiandrosterone sulphate (DHEAS). Our observations clearly show that DHEAS is neuroprotective both in pre- and post-traumatic administration and these results suggest that it may be of substantial therapeutic benefit for the treatment of traumatic injury. By using the mitotic marker BrdU we have found that cells destined to the glomerular and granule cell layers react in the same way to chronic estrogen treatment, and the effect of 17 β-estradiol on the neurogenesis and neuron survival is region specific within the adult olfactory bulb

Intercelluláris funkciós molekulák működése agyi endotélsejtekben = The function of junctional molecules in cerebral endothelial cells

Kutatásaink során az interendotheliális kapcsolatok szerepét vizsgáltuk elsősorban patológiás körülmények között. Megállapítottuk, hogy agyi endotélsejtekben az oxidatív stressz genotoxikus hatással rendelkezik és a MAPKinázok aktiválódásához illetve az occludin expressziójának jelentös csökkenéséhez vezet. Az occludin lebontásában az itch nevű ubiqiutin ligáz illetve a proteaszómák játszhatnak fontos szerepet. Kimutattuk, hogy a vérzéses shock az irreverzíbilis stádiumban a vér-agy gát áteresztőképességének fokozódásához vezet, amely hátterében az occludin downregulációja lehet. További kísérleti eredményeink arra engednek következtetni, hogy a tirozin foszforilációnak fontos szerepe lehet a junkcionális fehérjék működésének szabályozásában. Ezen túlmenően a ZO2 a sejtmagba vándorolva és a SAF-B nevű fehérjéhez kapcsolódva jeltovábbító molekulaként képes működni. Kimutattuk hogy a beta-catenin src által mediált tirozin foszforlációja jelentős szerepet játszhat a hiperozmotikus mannitol által indukált vér-agy gát permeabilitás fokozódás mechanizmusában. | Our research was focused on the study of the role of interendothelial junctions under pathological conditions. We have shown that oxidative stress has a genotoxic effect in cerebral endothelial cells, can lead to the activation of MAPKinases and to the downregulation of the tight junction molecule occludin. In the downregulation of occluding the ubiquitin ligase itch and the proteasomes may play a crucial role. We have demonstrated that hemorrhagic shock can lead an increase in the permeability of the blood-brain barrier, which could be mediated by the downregulation of occludin. Our experiments have demonstrated that tyrosine phosphorylation could play an important role in the regulation of junctional proteins. Furthermore we have shown that ZO2 may enter the nucleus and by binding to the SAF-B protein may play an active role in signal transduction. We have shown that src mediated tyrosine phosphorylation of beta-catenin could be an important step in the hyperosmotic mannitol induced opening of the blood-brain barrier

In Vitro and In Vivo Effect of Poplar Bud Extracts on Phytophthora infestans: A New Effective Biological Method in Potato Late Blight Control

The effect of populin extract from black poplar (Populus nigra) on seven different late blight strains was tested under laboratory and field conditions. The growth rate of hyphae was found to be significantly lower in vitro after 3 and 4 v/v% populin applications. Stain M16 was resistant to populin treatment under lab conditions, however. Both 5% and 10% concentration populin reduced the M16 strain’s severity on potato leaves under field conditions and proved to be even more effective than conventionally used fungicides Infinito 687 Sc and Valis M. Higher infection intensity at the 1% level was observed after 24 h using Valis M, and the same trend toward 10% infection remained after 48 and 72 h as well. Low, almost-no-infection intensity was detected after populin 5% and 10% treatment under an open field condition. Altogether, it can be concluded that populin extract can be a low-cost option for growers and an environmentally friendly approach in late blight control

Impact of aging on calcium influx and potassium channel characteristics of T lymphocytes.

Adaptive immunity and T cell function are affected by aging. Calcium influx patterns, regulated by Kv1.3 and IKCa1 potassium channels, influence T cell activation. We aimed to compare calcium influx kinetics in CD8, Th1 and Th2 cells in human peripheral blood samples obtained from five different age groups (cord blood, 10-15 ys, 25-40 ys, 45-55 ys, 60-75 ys).We measured calcium influx using flow cytometry in samples treated with or without specific inhibitors of Kv1.3 and IKCa1 channels (MGTX and TRAM, respectively).Calcium influx was higher in Th1 cells of adults, however, its extent decreased again with aging. Importantly, these changes were not detected in Th2 cells, where the pattern of calcium influx kinetics is similar throughout all investigated age groups. MGTX had a more pronounced inhibitory effect on calcium influx in Th2 cells, while in Th1 cells the same was true for TRAM in the 25-40 ys and 45-55 ys groups. Calcium influx of CD8 cells were inhibited to a similar extent by both applied inhibitors in these groups, and had no effect in the elderly.Altered lymphocyte potassium channel inhibitory patterns, regulators of calcium influx kinetics, might contribute to the development of age-related changes of T cell function

Associational susceptibility of crop plants caused by the invasive weed Canadian goldenrod, Solidago canadensis, via local aphid species

In the present study, field surveys were conducted to detect potential associational susceptibility of crop plants (potato, alfalfa and maize) caused by Canadian goldenrod, Solidago canadensis (L.), one of the most common invasive weeds in Central and Eastern Europe, via plant associated virus vectoring aphids. Assessments were made in two major agricultural land types: crops grown under high input vs. low-input (LIF) conditions, with and without fertilizers and pesticides. The two most frequent aphid species, found both on Canadian goldenrod and crop plants, were the leaf-curling plum aphid, Brachycaudus helichrysi Kaltenbach and the glasshouse-potato aphid, Aulacorthum solani (Kaltenbach). Plant viruses in both weed and crop plants were identified using high-throughput sequencing of small RNAs. Peroxidase (POD) enzyme activity was tested in weed and crop plants to connect aphids feeding processes in weeds and crops. In addition, conceptual modeling was used to detect direct relationships between viruses and other crops. The Canadian goldenrod density was only relevant in the LIF regime. Furthermore, its association with B. helichrysi and associational susceptibility was detected only in LIF. In total, 18 viruses comprising 17 plant and one insect virus were detected in Canadian goldenrod, of which 11 were also detected in potato and alfalfa crops. POD activity was high and correlated with high aphid density in both weed and crop plants, suggesting a direct associational susceptibility between these plants through aphid infestation and viral transmission

Impact of aging on calcium influx and potassium channel characteristics of T lymphocytes

Adaptive immunity and T cell function are affected by aging. Calcium influx patterns, regulated by Kv1.3 and IKCa1 potassium channels, influence T cell activation. We aimed to compare calcium influx kinetics in CD8, Th1 and Th2 cells in human peripheral blood samples obtained from five different age groups (cord blood, 10-15 ys, 25-40 ys, 45-55 ys, 60-75 ys).We measured calcium influx using flow cytometry in samples treated with or without specific inhibitors of Kv1.3 and IKCa1 channels (MGTX and TRAM, respectively).Calcium influx was higher in Th1 cells of adults, however, its extent decreased again with aging. Importantly, these changes were not detected in Th2 cells, where the pattern of calcium influx kinetics is similar throughout all investigated age groups. MGTX had a more pronounced inhibitory effect on calcium influx in Th2 cells, while in Th1 cells the same was true for TRAM in the 25-40 ys and 45-55 ys groups. Calcium influx of CD8 cells were inhibited to a similar extent by both applied inhibitors in these groups, and had no effect in the elderly.Altered lymphocyte potassium channel inhibitory patterns, regulators of calcium influx kinetics, might contribute to the development of age-related changes of T cell function

Endosymbiotic bacterial diversity of corn leaf aphid, Rhopalosiphum maidis Fitch (Hemiptera: Aphididae) associated with maize management systems

In this study, different maize fields cultivated under different management systems were sampled to test corn leaf aphid, Rhopalosiphum maidis, populations in terms of total and endosymbiotic bacterial diversity. Corn leaf aphid natural populations were collected from traditionally managed maize fields grown under high agricultural and natural landscape diversity as well as conventionally treated high-input agricultural fields grown in monoculture and with fertilizers use, hence with low natural landscape diversity. Total bacterial community assessment by DNA sequencing was performed using the Illumina MiSeq platform. In total, 365 bacterial genera were identified and 6 endosymbiont taxa. A high abundance of the primary endosymbiont Buchnera and secondary symbionts Serratia and Wolbachia were detected in all maize crops. Their frequency was found to be correlated with the maize management system used, probably with fertilizer input. Three other facultative endosymbionts (“Candidatus Hamiltonella”, an uncultured Rickettsiales genus, and Spiroplasma) were also recorded at different frequencies under the two management regimes. Principal components analyses revealed that the relative contribution of the obligate and dominant symbiont Buchnera to the aphid endosymbiotic bacterial community was 72%, whereas for the managed system this was only 16.3%. When facultative symbionts alone were considered, the effect of management system revealed a DNA diversity of 23.3%

Lézerek az optikában, spektroszkópiában és az anyagtudományokban = Lasers in optics, spectroscopy and material sciences

Ezen pályázat eredményei az SzTE Fizika Doktori Iskola négy tudományos részterületén (femtoszekundumos optika, lézerek anyagtudományi alkalmazása, valamint csillagászati- és fotoakusztikus spektroszkópia) dolgozó kollektíva egymással összefüggő, azt kiegészítő tudományos munkája révén jöttek létre, melyek főbb eredményei a következőek: Egy új, csak lineáris optikai eljárást fejlesztettünk ki lézerimpulzusok hordozó-burkoló fázis csúszásának mérésére, mely független a hullámhossztól és a sávszélességtől. Immerziós, két-nyalábos interferenciás lézerindukált hátsóoldali nedves maratási eljárást alkalmazva 104 nm periódusú kvarc rácsot készítettünk. A lézerrel generált fém-dielektrikum rácsok periódikus adhézió- és plazmon-mező modulációján alapuló új SPR bio-szenzorizációs eljárást dolgoztunk ki. Folyadékok ultrarövid impulzusokkal történő ablálásával kontrollált méreteloszlású és összetételű nanorészecskék előállításának új módszerét dolgozták ki. AFM fejlesztés során egy új amplitúdó és fázismérési algoritmust dolgoztunk ki, amely egyetlen rezgésből is képes az amplitúdó és fázis meghatározására. Kifejlesztettünk egy lézeres ammóniamérő műszert, amely alkalmas koncentráció és fluxus nagyérzékenységű, automatikus mérésére, terepi körülmények között. Nagyfelbontású spektroszkópiával kimutattuk, hogy két módusban rezgő csillagokban a nagyobb fémtartalmúaknál a rezgési periódusok aránya kisebb. | The results of this project have been achieved by the co-operative work of colleagues from four scientific fields of the Physics PhD Program of the University of Szeged, as femtosecond optics, laser-matter (surface) interactions, photoacoustical and astronomical spectroscopy. The major findings of these basic researches are as follows: A new linear optical method was developed for the measurement of the carrier envelope phase drift of laser pulses, which is independent of the wavelength and bandwidth. Immersion two-beam interferometric laser induced backside wet etching method was applied to prepare fused silica gratings with a 104 nm period. Novel SPR bio-sensing method was developed based on the periodic adhesion and plasmon-field enhancement on the laser-induced metal-dielectric gratings. It has been demonstrated that ultrashort pulse ablation of liquids is a novel approach to the production of nanoparticles of controlled composition and size distribution. A new amplitude and phase measurement algorithm for AFM was developed, which allows the determination of phase and amplitude from one vibration of the tip. We have developed a laser based instrument for accurate and automatic ammonia concentration and flux monitoring under field conditions. From high-resolution spectroscopy we pointed out that in double-mode pulsating stars the ones with higher metallicities have lower period ratios