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  • Author or Editor: E. Balázs x
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In this short note a protocol was summarized based on almost a decade of experience on the regeneration and transformation of pepper. The recipe presented could be used efficiently in the genetic engineering of pepper. The essence of the regeneration and transformation of pepper is derived from detailed descriptions previously published by the authors on how the method was developed.

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Molecular characterization of proliferating carnation plant tissues revealed association with a pararetroviroid-like agent. Carnation small virod-like RNA termed as CarSV RNA is unique among plant viroidlike RNA s by having a homologous DNA counterpart in the plant genome. Previously, CarSV DNA related sequences had been detected in the plant genome fused to microsatellite-like genomic sequences. Here we present data that tissue proliferation symptoms can be seen only on those plants that are expressing the RNA form of this agent. As CarSV RNA adopts a hammerhead structure in both polarities and the plant genome naturally encodes a functional hammerhead ribozyme, it can be concluded that these ribozyme sequences are cleaved out from the plant genome. This could lead to the evolution of small RNA s that replicate autonomously by the rolling circle mechanism and later could spread horizontally by vegetative propagation of the plant material, or by using a hitchhiked plant pararetrovirus fused to its genome.

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Mechanochemistry of sulphides

From minerals to advanced nanocrystalline materials

Authors: P. Baláž and E. Dutková

Abstract  

At present mechanochemistry of sulphides appears to be a science with a sound theoretical foundation exhibiting a wide range effectiveness in different areas of science and technology. For traditional application mechanochemistry is of exceptional importance in extractive metallurgy of sulphidic ores where many technological processes have been developed. Metal sulphides can be also utilized in emerging nanotechnology with application as advanced luminescence, optoelectronic, magnetic and catalytic materials.

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Abstract  

The reduction of cinnabar (HgS) and stibnite (Sb2S3) by hydrogen was investigated. These investigations were performed in the temperature region 636–765 K for cinnabar and in the region 825–954 K for stibnite. It has appeared that the mechanical activation positively affects the thermal reduction of the sulphides. The thermal decomposition of HgS is accompanied by a change in mechanism taking place at 744 K. As to Sb2S3, the change in mechanism inthe investigated temperature region was not observed.

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During our recent four years epidemiological studies ofMaize dwarf mosaic virus (MDMV) populations in Hungary, when 86 virus isolates were collected and analysed, a unique nucleic acid sequence variant was found in the 3’end region of the viral genome. According to our sequence studies, which also included all available MDMV sequences from different databanks, the coat protein region of the viral genome prooved to be quite identical. However, in several cases an insertion was located in the same position of the coat protein region. In the unique sequence variant we also found a 27 nt deletion in addition to the insertion. According to the extensive sequence search this deletion is unique and have been located only in two other potyvirus coat protein regions, while never in the case of MDMV. The potential role of this deletion in the virus infectivity, replication or other biological characteristics is discussed.

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The coat protein gene (CP) from a highly virulent, necrotic and dominant strain of potato virus Y (PVY) originated from the Hungarian flora has been engineered via Agrobacterium infection into different Hungarian tobacco breeding lines and cultivars. The integration of the CP was confirmed by polymerase chain reaction (PCR) using genomic prepa­ra­tions. The transcription and the expression of the integrated CP gene were detected by Northern and Western analysis. The pathogen-derived resis­tance was demonstrated by inoculation of the R1 progeny of transformant plants with purified PVY. The efficiency of the protection varied between different transgenic tobaccos ranging from complete to no protection. The challenge infection of the plants was monitored by dot blot hybridisation at different intervals after mechanical inoculation. Western blot analysis showed that there is no correlation between the level of expressed CP and the extent of resistance. From tobacco cultivars namely Virgin D, Stamm C2 and Hevesi 11, 38, 55 and 23 transformants were obtained, respectively. After several years of greenhouse expe­ri­ments, only the extreme resistant tobaccos were planted field under the special licence, given by the competent authority. In field conditions, transgenic tobacco varieties showed extreme resistance against natural infection of PVY.

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Authors: E. Rapavi, K. Szentmihályi, A. Lugasi, E. Vági, É. Bányai, A. Balázs, É. Szőke and A. Blázovics

The different methods of making herbal tea used in various cultures may decrease the efficiency of herbal tea, therefore the purpose of the present study was to examine the changes in antioxidant activity and metal ion concentration in aqueous extracts of “Tieguanyin Stomach Tea” obtained with different steeping times. Partial phytochemical examination, element analysis, and the determination of antioxidant properties were carried out. High Al, Cr, Mn, Ni, Pb and Ti content was observed in the tea drug. Aqueous extracts of the drug sample showed H-donor activity, reducing power and scavenging activity, depending on the steeping time and concentration. According to our findings, 5-min steeping was the least effective and redox parameters of the aqueous extracts did not change considerably between 15 and 120 min of steeping time.

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An efficient regeneration system is described based on the use of several genotypes and combining different cytokinins in the regeneration process. Optimal regeneration efficiency can be obtained if the factors affecting regeneration are examined with special attention to the maintenance of the stock plants, the composition of the medium, and the pre-treatment. The maintenance of stock plants proved to be optimal if the plants were kept on modified LS medium supplemented with 0.125 mg L −1 6-benzylaminopurine (BAP) and 0.01 mg L −1 indole-3-butyric acid (IBA) in large vessels. Pre-treatment was found to increase the regeneration efficiency. Placing the leaves on to medium containing 1.5 mg L −1 BAP-riboside and 0.1 mg L −1 thidiazuron (TDZ) without wounding, and keeping them in the dark for 6 days gave the best results. The highest regeneration rate was observed on medium containing MS salts with B5 vitamins complemented with 20 g L −1 glucose, 3 mg L −1 BAP-riboside, 0.2 mg L −1 TDZ and 0.2 mg L −1 IBA. This system made it possible to achieve regeneration in each of the varieties examined, though to different extents.

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