VARIABILITY OF PHOTOSYNTHETIC PARAMETERS IN A SHALLOW TEMPERATE COASTAL AREA (GULF OF TRIESTE, ADRIATIC SEA)

Abstract We studied the relationship between physico-chemical factors and photosynthetic parameters. P was mostly affected by temperature and phosphate. Overall, photosynthetic parameters showed less variability over the annual cycle in contrast to environmental factors and phytoplankton biomass

The biological fate of silver nanoparticles from a methodological perspective

We analyzed the performance and throughput of currently available analytical techniques for quantifying body burden and cell internalization/distribution of silver nanoparticles (Ag NPs). Our review of Ag NP biological fate data shows that most of the evidence gathered for Ag NPs body burden actually points to total Ag and not only Ag NPs. On the other hand, Ag NPs were found inside the cells and tissues of some organisms, but comprehensive explanation of the mechanism(s) of NP entry and/or in situ formation is usually lacking. In many cases, the methods used to detect NPs inside the cells could not discriminate between ions and particles. There is currently no single technique that would discriminate between the metals species, and at the same time enable localization and quantification of NPs down to the cellular level. This paper serves as an orientation towards selection of the appropriate method for studying the fate of Ag NPs in line with their properties and the specific question to be addressed in the study. Guidance is given for method selection for quantification of NP uptake, biodistribution, precise tissue and cell localization, bioaccumulation, food chain transfer and modeling studies regarding the optimum combination of methods and key factors to consider

Fine-tuning of proximal TCR signaling by ZAP-70 tyrosine residues in Jurkat cells

Zeta-chain-associated protein kinase of 70kDa (ZAP-70) kinase is a key regulator in the early steps of TCR signaling but some aspects of its fine regulation are still unclear. From its 31 tyrosine (Y) residues, 11 phosphorylation sites have been identified, some with activator (Y315 and Y493) or inhibitory (Y292 and Y492) and others with unknown function (Y069, Y126 and Y178). In our present work, we aimed to elucidate the role of different Y residues of ZAP-70, especially those with unknown function, in calcium signaling and the autoregulation of the kinase. ZAP-70-deficient Jurkat cells (P116) were stably reconstituted with point-mutated ZAP-70 constructs where tyrosine residues 069, 126, 178, 238, 292, 315, 492 or 493 were replaced with phenylalanine (F). The anti-CD3-elicited calcium signal increased in F069-, F292- and F492-ZAP-70-expressing cell lines but decreased in the F126-, F315- and F493-ZAP-70-expressing cell lines. ZAP-70 point mutations led to phosphorylation changes predominantly in SH2 domain containing leukocyte protein of 76kDa (SLP-76) but not linker of activated T cells (LAT) during CD3-activation; moreover, we detected basal hyperphosphorylation of SLP-76 Y128 in the F126-, F178- and F492-ZAP-70-expressing cell lines. In summary, Y069, Y178, Y292 and Y492 have inhibitory, while Y126, Y315 and Y493 activator role in anti-CD3-induced T-cell activation. Phosphorylation changes in LAT and SLP-76 suggest that fine regulation of ZAP-70 on calcium signaling is rather transmitted through SLP-76 not LAT. Additionally, negative or positive autoregulatory function of Y292 and Y493 or Y315, respectively, was revealed in ZAP-70. These data indicate that previously not characterized Y069, Y126 and Y178 in ZAP-70 participate in the fine regulation of TCR signaling

First report of maize redness disease in Hungary

Abstract During 2010, several maize production areas in Hungary were surveyed for the occurrence of maize redness (MR) disease symptoms associated with stolbur phytoplasma, as well as for the presence of the known vector of the disease, a planthopper Reptalus panzeri (Low). Incidence of maize plants with symptoms of reddening was low in all surveyed areas. Altogether, 25 symptomatic maize plants were collected at 9 localities and tested for phytoplasma presence. In addition, from one locality specimens of cixiids R. panzeri and Hyalesthes obsoletus Signoret were collected and PCR analyzed. Presence of stolbur phytoplasma in MR symptomatic maize plants and stolbur-infected R. panzeri was identified at the single locality Monorierdő in central Hungary. This finding represents the first report of MR presence in Hungary

Catecholaminergic signalling through thymic nerve fibres, thymocytes and stromal cells is dependent on both circulating and locally synthesized glucocorticoids

Glucocorticoids have been shown to modulate the expression of noradrenaline metabolizing enzymes and beta(2)- and alpha(1B)-adrenoceptors in a tissue- and cell- specific manner. In the thymus, apart from extensive sympathetic innervation, a regulatory network has been identified that encompasses catecholamine-containing non-lymphoid and lymphoid cells. We examined a putative role of adrenal- and thymus-derived glucocorticoids in modulation of rat thymic noradrenaline levels and adrenoceptor expression. Seven days postadrenalectomy, the thymic levels of mRNAs encoding tyrosine hydroxylase, dopamine beta-hydroxylase, monoamine oxidase-A and, consequently, noradrenaline were decreased. Catecholamine content was diminished in autofluorescent nerve fibres (judging by the intensity of fluorescence) and thymocytes (considering HPLC measurements of noradrenaline and the frequency of tyrosine hydroxylase-positive cells), while it remained unaltered in non-lymphoid autofluorescent cells. In addition, adrenalectomy diminished the thymocyte expression of beta(2)- and alpha(1B)-adrenoceptors at both mRNA and protein levels. Administration of ketoconazole (an inhibitor of glucocorticoid synthesis/action; 25 mg kg(-1) day(-1), s.c.) to glucocorticoid-deprived rats increased the thymic levels of tyrosine hydroxylase, dopamine beta-hydroxylase and, consequently, noradrenaline. The increased intensity of the autofluorescent cell fluorescence in ketoconazole-treated rats indicated an increase in their catecholamine content, and suggested differential glucocorticoid-mediated regulation of catecholamines in thymic lymphoid and non-lymphoid cells. In addition, ketoconazole increased the thymocyte expression of alpha(1B)-adrenoceptors. Thus, this study indicates that in the thymus, as in some other tissues, glucocorticoids not only act in concert with cateholamines, but they may modulate catecholamine action by tuning thymic catecholamine metabolism and adrenoceptor expression in a cell-specific manner. Additionally, the study indicates a role of thymus-derived glucocorticoids in this modulation