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  • Author or Editor: Z. Szigeti x
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The fluorescence imaging technique was elaborated primarily for the detection of the fluorescence traits accompanying changes in the physiological status of stressed plants. The paper summarises the conditions and technical background required for the use of multi-wavelength fluorescence imaging. Images of leaves were recorded at wavelengths of 440, 520, 690 and 740 nm. Possible applications are illustrated by studies on the leaves of stressed plants. An evaluation of the images is presented, including the necessary corrections and fluorescence ratios, examples of comparisons between imaging and functional activity measurements, and an evaluation of the diagnostic importance and reliability of imaging in detecting the effects of stressors in plants. The results demonstrate that the multi-wavelength fluorescence imaging of leaves is a useful method for detecting the presence of stress in plants and for determining the extent of the stress.

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We investigated the dendritic patterns of rapid Golgi-impregnated, highly similar multipolar neurons from two functionally different thalamic regions of the rat brain: two dorsal nuclei (the nucleus laterodorsalis thalami, pars dorsomedialis and the nucleus laterodorsalis thalami, pars ventrolateralis), and two ventral nuclei (the nucleus ventrolateralis thalami and the nucleus ventromedialis thalami). The analysis involved conventional morphometric parameters (height and size) and a new parameter derived from graph theory, the relative imbalance (RI), derived from the branching patterns of the dendrites, which permits quantitative characterization of the dendritic arborization of a neuron. On this basis, neurons can be grouped into three fundamentally different types: type A, or highly-polarized (imbalanced) neurons (RI values close to 1); type B, or medium-polarized neurons (RI values around 0.5); and type C, or balanced neurons with low polarization (RI values close to 0). The orientations of the dendritic arbor, and thus the receptive fields, of the dorsal and ventral thalamic neurons, were mutually perpendicular. The H and S values indicated that the neurons in the dorsal and ventral thalamic nuclei differed significantly. However, their RI values demonstrated that they were similar neurons of type B. Our data reveal that 1) the dendritic arbor cannot be reliably characterized purely on the basis of height and size, and 2) RI is a valuable morphometric parameter that identifies the true nature of the dendritic arborization.

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Thirty-three varieties of dairy products were analysed for fat and cholesterol contents, and a high correlation (r=0.983) was found between these two compositional attributes. Cholesterol concentration was independent of processing factors such as heat-treatment of the raw material, use of starter culture, type of the starter organisms employed and whipping or flavouring of the product. The non-fat varieties of fluid, fermented and dried milks showed significantly increased cholesterol-to-fat ratios compared to the other products tested because they contained considerable amounts of small fat globules and, therefore, had a large surface area with cholesterol bound to the fat globule membranes. The results of this study may be useful when establishing dietary guidelines for the general public according to health concerns, when formulating diets for population groups with special requirements or when assessing fat and cholesterol intakes in epidemiological studies aimed at investigating the relationship between diet and health.

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Solar UV-B radiation is generally regarded as an environmental stress factor, causing harm to living organisms by damaging DNA, proteins, lipids and membranes. Increased UV-B radiation may affect plant life directly or indirectly, having an influence on photosynthesis and plant biomass. In many plants, including maize (which is one of the most important crops in the world), exposure to increased UV-B radiation causes the induction of UV-B absorbing compounds (e.g. flavonoids), which act as UV-B screens and reduce the dangerous levels and effects of this radiation in plant tissues and cells.This study aimed to reveal how Martonvásár maize inbred lines (bred under Central European environmental conditions) respond to increased UV-B radiation.

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The research aims to examine the health conscious consumer behaviour on the market of functional foods. In the survey two focus groups with 8 participants from two Hungarian cities were involved. People, whose health behaviour has changed positively in the past few years, were chosen to take part in the focus groups. The respondents connected the concept of health consciousness to the conscious way of life, nutrition and active physical exercises as well. Most of them are interested in the possibilities of healthy nutrition, they consider themselves capable of controlling their state of health, but only few of them take particular steps. The difference is caused by the lack of time and financial background, but the low level of motivations also plays a significant role. The consumers accept the presence of functional foods, which is interpreted as a long run innovation trend. They have limited information about functional ingredients; they do not know nutritional benefits and most of them are mistrustful of this product category. The organisations that are mainly responsible for information are not authentic for the consumers, but the authentic ones do not reach their stimulus threshold. Beliefs, attitudes, subjective norms do not exert enough influence on the consumers and perceived behavioural control does not reach that critical level at which these factors can motivate them to take particular steps.

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Acta Alimentaria
Authors: V. Szente, O. Szigeti, Zs. Polereczki, Á. Varga, and Z. Szakály

In Hungary, organic food market has both demand and supply oriented aspects: several times not necessary products are distributed, while the selection and volume of certain products are not satisfactory. Thus, our aim was to develop a coordinated benchmark strategy to increase the trade of organic products. To get more details on the Hungarian organic milk market, we conducted professional deep interviews and simultaneously applied the “mystery shopping” method. Nowadays, the market of organic milk and dairy products is slowly increasing in Hungary, however, there is no available statistical data. In the selection there are mostly Hungarian originated products, but some yoghurt, milk, and butter assortments are imported. Partial responsibility belongs to small sale shops’ habit of risk-avoidance. Without a proper selection of products, stores are unable to satisfy consumers’ needs; thus they focus on pushing certain products to increase demand. According to our results, ‘low price category’, ‘local/regional product’, and ‘prestige product’ strategies with attached in-store marketing elements are able to reverse the effects of an unfavourable marketing process.

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Acta Agronomica Hungarica
Authors: J. Pintér, E. Kósa, G. Hadi, Z. Hegyi, T. Spitkó, Z. Tóth, Z. Szigeti, E. Páldi, and L. Marton

The level of UV-B radiation reaching the surface of the earth is increasing due to the thinning of the ozone layer in the stratosphere over recent decades. This has numerous negative effects on living organisms.Some of the Hungarian inbred maize lines examined under the climatic conditions in Chile exhibited an unusually high proportion of pollen mortality, flowering asynchrony and barrenness. The evidence suggests that this can be attributed to the approx. 30% greater UV-B radiation in Chile.The investigation of this problem within the framework of abiotic stress breeding programmes is extremely important in the light of the global rise in UV-B radiation, which may make it necessary to elaborate a selection programme to develop inbred lines with better tolerance of this type of radiation.In the course of the experiment the same ten inbred lines, having different maturity dates and genetic backgrounds, were tested for five years in Chile and Hungary. The tests focussed on anthocyanin, a flavonoid derivative involved in the absorption of damaging UV-B radiation.Averaged over years and varieties, the total anthocyanin content in the leaf samples was significantly higher in Chile than in Hungary. This was presumably a response at the metabolic level to the negative stress represented by higher UV-B radiation.In the five early-maturing flint lines the anthocyanin contents were more than 45% greater than those recorded in Hungary. This suggests that these genotypes, originating from northern regions, were not sufficiently adapted to the higher radiation level. In these samples higher UV-B caused a sharp rise in the quantity of anthocyanin, which absorbs the dangerous radiation. In late-maturing genotypes the initial content of the protective compound anthocyanin was higher at both locations, so in these types the high radiation level was not a problem and did not cause any substantial change.Similar conclusions were drawn from the results of fluorescence imaging. The F440/F690 ratio indicative of the stress level was higher in late lines with a high anthocyanin content, good tolerance and good adaptability.

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The work was aimed at investigating short-term metabolic changes caused by S-methylmethionine (SMM) and at clarifying the gene expression background of these changes in order to gain a better understanding of the protective effect of SMM against stress. When examining the expression of genes coding for the enzymes responsible for the biosynthesis of polyamines, which play an important role in responses to low temperature stress, and that of the C-repeat binding transcription factor (CBF1) gene, it was found that both SMM and cold treatment increased the expression of genes responsible for the polyamine synthesis pathway starting from arginine. It caused only a slight increase when applied alone, but when SMM pre-treatment was followed by cold stress, it resulted in a considerable extent of up-regulation. SMM caused a similar increase in the expression of CBF1. The changes in the expression of genes responsible for the polyamine synthesis were clearly reflected in changes in the putrescine and agmatine contents, while the greater increase in the spermidine content was indicative of the role of SMM as a direct precursor in spermidine biosynthesis. The results demonstrated that, in addition to its direct effect on the sulphur metabolism and on polyamine biosynthesis, the protective effect of exogenous SMM was chiefly manifested in its influence on the expression of genes responsible for the biosynthesis of the polyamines important for stress responses and on the CBF1 transcription factor gene that acts as a regulator in cold stress.

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