In Vitro Callus Induction from Adult Tissues of Japanese Flowering Cherry Trees and Two Cherry Rootstocks

Several in vitro biotechnological techniques have been developed, all of which require a reliable protocol to produce a responsive callus mass. One of these techniques is callus fusion in vitro, which is reliable for the early detection of (in)compatibility of scions and rootstocks. In this paper, the possibility to obtain friable callus tissues was explored by callus induction of adult tissues of Japanese flowering cherry trees from the group Sato zakura (Prunus serrulata 'Amanogawa', 'Kanzan' and 'Kiku-shidare-zakura') and two domestic cherry rootstocks -Prunus avium and Prunus 'Colt'. The explants used in the research were: leaf petiole, leaf base with a part of a petiole, part of lamina with a midvein and a stem with an axillary bud. Among three plant growth media (MS, SH and WP) that were used in this study, the MS proved to be the most favourable for the majority of taxa during the callus induction process. For the sweet cherry tree and the cultivars 'Kanzan' and 'Colt', the SH plant growth medium was also acceptable. The best results in callogenesis were obtained for the majority of taxons with auxin at the concentration 2 mgL-1 NAA and cytokinin BAP 0.5 mgL-1. It is also possible to use 2.4-D at the same concentration as a substitute for the genotypes Prunus avium, Prunus ` Colt' and Prunus serrulata 'Kanzan', whereas IBA proved to be an inappropriate auxin for callus induction. The protocol described herein is proved to be efficient callus induction in a range of taxa of genus Prunus

Homocysteine serum levels and MTHFR C677T genotype in patients with Parkinson's disease, with and without levodopa therapy

Both methylenetetrahydrofolate (MTHFR) C677T genotype and levodopa treatment may give rise to elevated serum homocysteine levels in parkinsonian patients. We aimed to clarify the interplay of these factors in pathogenesis of Parkinson's disease (PD)-related hyperhomocysteinemia. Total serum levels of homocysteine (tHcy) and MTHFR C677T genotype were investigated in levodopa-treated and -untreated parkinsonian ("de novo") patients, as well as in control healthy subjects matched by age and gender (N=83, 30 and 53, respectively). MTHFR C677T genotypes were equally distributed in PD patients and control subjects, the T allele homozygosity being observed in app. 12-17% cases. tHcy concentrations were significantly higher in both levodopa-treated and -untreated PD patients than in control subjects, and in TT homozygotes than in CT or CC genotype carriers. tHcy levels significantly correlated with the duration of the disease in PD treated patients only, reaching the maximum after 3-6 years. However, there was no correlation between tHcy levels and total daily intake of levodopa in the same group of PD patients. In conclusion, MTHFR C677T genotype is a significant factor for hyperhomocysteinemia. in patients with PD, levodopa-untreated and probably even more in levodopa-treated PD patients

Processing and properties of pure antiferromagnetic h-YMnO3

Yttrium manganite (YMnO3) is widely investigated multiferroic material with potential use in many technological applications. In this paper, we report on the preparation and characterization of multiferroic hexagonal YMnO3 ceramics obtained by chemical synthesis route. Precursor powders were prepared by the polymerizable complex method from citrate precursors. After calcination at 900 degrees C the powders contained mixture of Y-Mn-O phases which were further sintered at different temperatures. XRD analysis revealed that sintering at 1400 degrees C resulted in the formation of pure hexagonal YMnO3. Density of the obtained ceramics was 96 %TD. The ceramic samples proved to have multiferroic properties - they are antiferromagnetic below 42 K with linear dependence of magnetization as a function of applied magnetic field. The ferroelectric measurements performed at room temperature showed remanent polarization of 0.21 mu C/cm(2) and the coercive field of 6.0 kV/cm for the YMnO3 sample sintered at 1400 degrees C. The magnetization curves measured at 2 and 5 K for the powder samples calcined at 900 degrees C and ceramic samples sintered at 1300 degrees C exhibited a hysteresis loop due to a small concentration of Mn3O4 in the samples

Molecular characterization and phylogenetic analysis of full-genome HBV subgenotype D3 sequences from Serbia

Hepatitis B virus (HBV) is classified into 8 genotypes with distinct geographical distribution. Genotype D (HBV/D) has the widest distribution area and is comprised of 7 subgenotypes. Subgenotypes D1, D2 and D3 appear worldwide, while D4-D7 have a more restricted distribution. Within the Mediterranean area, HBV/D and subgenotype D3 are the most prevalent. The purpose of this study was to characterize the full genome of Serbian HBV/D3 isolates by comparison and phylogenetic analysis with HBV/D3 sequences (66 samples) found in GeneBank/DDBJ databases from different parts of the world. Isolates were obtained from three patients diagnosed with chronic hepatitis B (HBsAg +). All three isolates have two very rare nucleotide substitutions, A929T and T150A, which indicate the same ancestor. Phylogenetic analysis of HBV/D3 genome sequences throughout the world follows an ethno-geographical origin of isolates with rare exceptions, which could be explained by human travelling and migration. The geographically close but ethnically different Serbian and Italian isolates clustered in the same subnode, and on a common branch with strains from Northern Canada. To test the apparently close HBV phylogenetic relationship between completely separated patients from Serbia and Northern Canada we analyzed in depth a 440 bp region of the HBsAg from Canadian (n = 73) and Serbian (n = 70) isolates. The constructed parsimony tree revealed that strains from Serbia and Northern Canada fell along the same branch which indicates independent evolution within regions of each country, Considering that HBsAg sequence has limited variability for phylogenetic analyses, our hypothesis needs further confirmation with more HBV complete genome sequences. (C) 2011 Elsevier B.V. All rights reserved,Ministry of Science and Technological Development of the Republic of Serbia [173003, 173049