Danka Némethová

Publications (3)6 Total impact

• Article: Effects of conditional IPT-dependent cytokinin overproduction on root architecture of Arabidopsis seedlings.

  Alena Kuderová, Ivana Urbánková, Martina Válková, Jirí Malbeck, Bretislav Brzobohaty, Danka Némethová, Jan Hejátko
  [show abstract] [hide abstract]
  ABSTRACT: Cytokinin (CK) has been known to inhibit primary root elongation and suggested to act as an auxin antagonist in the regulation of lateral root (LR) formation. While the role of auxin in root development has been thoroughly studied, the detailed and overall description of CK effects on root system morphology, particularly that of developing lateral root primordia (LRPs), and hence its role in organogenesis is still in progress. Here we examine the effects of conditional endogenous CK overproduction on root architecture and consider its temporal aspect during the early development of Arabidopsis thaliana. We employed the pOp/LhGR system to induce ectopic ipt overexpression with a glucocorticoid dexamethasone at designated developmental points. The transient CaMV 35S>GR>ipt transactivation greatly enhanced levels of biologically active CKs of zeatin (Z)-type and identified a distinct developmental interval during which primary root elongation is susceptible to increases in endogenous CK production. Long-term CK overproduction inhibited primary root elongation by reducing quantitative parameters of primary root meristem, disturbed a characteristic graded distribution pattern of auxin response in LRPs and impaired their development. Our findings indicate the impact of perturbed endogenous CK on the regulation of asymmetric auxin distribution during LRP development and imply that there is cross-talk between auxin and CK during organogenesis in A. thaliana.
  Plant and Cell Physiology 04/2008; 49(4):570-82. · 4.70 Impact Factor
• Article: The course of diagnosis in autistic patients: the delay between recognition of the first symptoms by parents and correct diagnosis.

  Hana Oslejsková, Ivana Kontrová, Renata Foralová, Ladislav Dusek, Danka Némethová
  [show abstract] [hide abstract]
  ABSTRACT: The primary aim of the research was to find the delay between the first symptoms of an autistic disorder being recognized by parents and diagnosis in our centre. A secondary objective was to evaluate the number of contacts with professionals (physicians, teachers, and speech therapists) in which parents pointed out special manifestations seen in children and, in spite of that, the children were not referred to a specialist. A retrospective study assessed 204 children (59 girls, 145 boys) in total; 126 children (39 girls, 87 boys) with childhood autism (CHA), 57 (17 girls, 40 boys) with atypical autism (AA), and 21 (3 girls, 18 boys) with Asperger's syndrome (AS). The mean age at appearance of the first signs was 29.7 months (range 0-70, median 30+/-17.0) in N=201, and the average age at diagnosis was 81.5 months (range 13-276, median 69.5+/-45.2) in N=204. The mean delay in making a diagnosis was 51.3 months (range 0-246, median 39+/-40.9) in N=201. The delay in diagnosis is shortest in patients with AA (a mean period of 44.4 months = 3 years and 8 months), longer in CHA patients (49.5 months = 4 years and 2 months), and longest in patients with AS (80.8 months = 6 years and 9 months). A statistically significant difference in the period to diagnosis was found between CHA and AS patients (p=0.023) and between AA and AS patients (p=0.019). The mean number of visits to physicians and other specialists before referring to a specialized centre for diagnosis in N=133 was 2.4 (range 1-5, median 2+/-0.9). The diagnosis of autism is made late and early educational and behavioural interventions cannot be initiated.
  Neuro endocrinology letters 01/2008; 28(6):895-900. · 1.30 Impact Factor
• Source

  Available from: akademickyrepozitar.sk

  Article: The composition and richness of Danubian floodplain forest land snail faunas in relation to forest type and flood frequency

  Tomás Cejka, Michal Horsák, Danka Némethová
  [show abstract] [hide abstract]
  ABSTRACT: The species richness and composition of land snail assemblages in 42 floodplain forest sites along the Danube River in Slovakia were studied to find the main ecological gradients responsible for the variation in the faunas. We found just one, but steep, ecological gradient influencing the variation of snail species composition among different floodplain forest types, reflected in the first detrended correspondence analysis axis, which explained 29.6% of total variation. Site scores on this axis were significantly correlated with site humidity ( r s =−0.868; P <0.001). Significant loading on the first axis was also found for flood frequency and several vegetation descriptors. Species composition mainly reflected differences between sites without floods and the others. Species richness as well as total abundances of live individuals were not significantly controlled by any explanatory variable, although some trends could be discerned. Considering vegetation classification, substantial differences were observed between wet softwood floodplain forests and the remaining types, drier softwood forests and different types of hardwood forests, which were impossible to distinguish based on land snail assemblages. The results are discussed in relation to earlier descriptive studies, and in terms of the conservation of these threatened habitats.