Search Results

You are looking at 11 - 20 of 50 items for

  • Author or Editor: B. Horváth x
  • Refine by Access: All Content x
Clear All Modify Search

Medium chain fatty acids are candidates of partial sulphur dioxide replacement in wine, as a solution to the growing consumer concerns about chemical additives. In botrytised sweet wine specialties, large amount of sulphur dioxide addition is one of the effective practices to stop alcoholic fermentation. Increasing medium chain fatty acid levels up to 80 mg l-1 was tested as a sole inhibitor on solid agar surface. S. bacillaris seemed to be the most sensitive, S. cerevsisiae and S. bayanus were more tolerant, while Z. bailii showed the highest tolerance. Then, increasing medium chain fatty acid levels up to 40 mg l-1 combined with 100 mg l-1 sulphur dioxide was introduced into a Tokaj Essence under refermentation. After 56 days, the highest dosage had pronounced effect on the yeast population, but the refermentation was not inhibited completely. Medium chain fatty acids have varying inhibitory effect on botrytised wine-related yeasts, moreover, it could be used effectively in media with high ethanol content, unlike Tokaj Essence.

Open access

During the ageing in barrels, the contact with the fine lees triggers several processes in wine. Lees has a reductive effect by absorbing dissolved oxygen and reducing the amount, which will remain in the wine. At present, minimizing the addition of sulphur dioxide is the trend in all viticultural areas. In this study, the effect of various sulphur dioxide levels was monitored in presence of the lees to determine which dose is appropriate to provide the protection of susceptible white wine against oxidation.

Without SO2 protection, the rH and redox potential changed slightly, so the level of dissolved oxygen seemed to be controlled during the ageing period by the lees, though the antioxidant effect of lees in itself was not appropriate to protect the polyphenol content from chemical oxidation, which led to considerable browning. With the addition of a lower amount of SO2 — 40 mg l2, the lees is already able to protect the white wine samples in all aspects.

Restricted access

Experiments were carried out on sperm cryopreservation of two European percid fish species, the pikeperch (Sander lucioperca) and the Volga pikeperch (S. volgensis) . Two experiments were conducted on pikeperch sperm. In the first, the effects of three extenders (Glucose, KCl, Sucrose) and two cryoprotectants (dimethyl-sulfoxide: DMSO, methanol: MeOH) were tested on motility and fertilization. In the second, the effects of two dilution ratios (1: 1, 1: 9) and two cryoprotectants (DMSO, MeOH) on hatching were investigated. In the experiment on Volga pikeperch the suitability of using cryopreservation for fertilization was investigated. In the first experiment on pikeperch the highest post-thaw motility (28 ± 21%) and fertilization rate (43 ± 12%) was found with DMSO as cryoprotectant in combination with Glucose extender. In the second, the highest hatch rate (41 ± 22%) was observed with MeOH as cryoprotectant and 1: 1 sperm dilution ratio, however no significant difference was found among the results. In the experiment on Volga pikeperch hatch rates with cryopreserved sperm (60 ± 2%) did not significantly differ from the control (60 ± 6%). Contamination of sperm with urine seems to be a key problem in the success of sperm cryopreservation of these species.

Restricted access

Agricultural goods obtained and produced in Hungary have played an important role in the markets of Western Europe. By utilizing the ecological potentials of the Carpathian Basin, local inhabitants are in the position to produce considerable food surpluses in addition to meeting their own demands. With agricultural production becoming more and more intensive in Hungary, the application of mineral fertilizers also started to increase slowly from the 1960’s. From the mid-1970’s a uniform sampling, soil testing and fertilization extension system was created together with its own institutional and laboratory testing network. The intensive use of mineral fertilizers in Hungary lasted from the mid-1970’s to the last quarter of the 1980’s, during which an average amount of 230 kg·ha -1 NPK fertilizer was applied. In this period the so-called “build-up” fertilization was applied in conformity with the improvement of all other elements involved in the production technology, which was also clearly expressed in the agro-political objectives of those days aiming to obtain higher yields. At that time the nutrient supply and nutrient base of soils in Hungary increased clearly, so the production technology could no longer limit higher yields. In 1990 agriculture changed fundamentally and radically in Hungary, and the same was valid for nutrient supplies as well. At the beginning of the 1990’s there was a sudden decrease in the level of mineral fertilizer application (to below 40 kg NPK active ingredients·ha -1 ), followed by a slow increase, which has reached the level of almost 70 kg·ha -1 by today. In the meantime the animal stock in Hungary has decreased and consequently the amount of manure has also fallen. All in all, the nutrient balance of Hungarian soils has always been negative since 1989. Due to the changes in its structure and ownership over the past twenty years or so, it has become very difficult to obtain reliable information about Hungarian agriculture. The Soil Resources Management General Partnership (in Hungarian: Talajerőgazdálkodás Kkt.) conducts extension work based on soil sampling and has a continuous flow of data on over thirty thousand hectares, beginning at the end of the 1970’s. Based on the analyses of these data it can be stated that the extra amount of nutrients over balance, applied during the period of replenishment (until the change in regimes) has been „removed” from the soil over the past fifteen years, consequently the Hungarian nutrient balance has become negative again. This kind of fertilization practice cannot be sustained in Hungary, as the maintenance of the production potential of Hungarian soils is far from being resolved at the moment; it poses risks to and questions sustainability, as well as it may cause a very serious competitive disadvantage to the country.

Restricted access

Certain classes of bioactive compounds can be separated using planar chromatography. Some biological effects (e.g. antibacterial) of these compounds can be investigated directly by examining the growth of a test organism on a specially treated sorbent of thin layer chromatography (TLC). A special method of detection, direct bioautography, is suitable for studying the antimicrobial activity of plant extracts of natural origin by using TLC. Zones of inhibition are visualised by use of a dehydrogenase-activity-detecting, tetrazol-type reagent. Zones of inhibition appeared as pale spots separating well from the dark background. The antibacterial effect of the main essential oil components of some Thymus taxa, as well as that of two antibiotics (streptomycin sulphate and gentamycin) known and applied in practice was investigated against plant pathogenic bacteria. Results showed that thyme essential oil and its components inhibited the growth of test bacteria, but not so considerably as the antibiotics applied. Compositions of the essential oils were analysed by gas chromatography (GC). It could be verified that among the essential oil components, thymol and carvacrol had the strongest inhibitory effect.

Restricted access

Regional habitat pattern of the Danube-Tisza Interfluve in Hungary II

The sand, the steppe and the riverine vegetation, degraded and regenerating habitats, regional habitat destruction

Acta Botanica Hungarica
Authors:
M. Biró
,
A. Révész
,
Zs. Molnár
,
F. Horváth
, and
B. Czúcz

The increased endangerment and rapid devastation of the vegetation on the Danube-Tisza Interfluve are quite complex processes that can be approached from a manifold ways. One of the most important factors having influenced the vegetation in the recent past is the decline of the groundwater-level, the extent of which is well known and the reasons for that have been investigated for a long time. However, only few have studied its dramatic effect on the vegetation outside the local scale. In the first part of our bipartite article we discuss the regional habitat-pattern of the landscape, the background factors determining it, and the basic features of fen and alkali vegetation (Biró et al. 2007). In this second part, this will be completed by the sand, riverine and steppe vegetation and the data on habitat devastation on the regional scale. The analysis of the present habitat-pattern of the region was based on data of the actual (1996–2000) habitat map of Danube-Tisza Interfluve (Molnár et al. 2000, Biró et al. 2003) and on our experiences during the field survey. The quantitative analysis of the vegetation pattern was carried out considering the vegetation subregions. Our aim is to expose the actual state of the landscape, the vegetation and the rapid devastation of the natural habitats, by quantifying the current processes.Our results demonstrate that the extension of those habitats on the Danube-Tisza Interfluve that were not under cultivation in the 1980s has decreased drastically, by 40,074 ha (approx. 15%). The main reasons for grassland devastations are ploughing, afforestation, the invasion of shrubs and trees, the building in activity and the establishment of open water surfaces. The most serious decline in the recent past was observed in the case of fen vegetation: the decrease of its extension was estimated to be 10–11%. More than half of the habitats disappeared as a result of ploughing and grassland-devastation due to urbanisation (building in, development of infrastructure, etc.) was covered by fen vegetation, while about a quarter of them consisted of alkali habitats. Sand areas mostly decline because of the spontaneous invasion of alien species and afforestation, which led to the devastation of approx. 4% of the natural and disturbed sand vegetation. Astonishing is the fact that the total extension of the more-or-less disturbed or devastated habitats altogether comprise roughly half (49%) of the actually mapped vegetation patches of the Interfluve (137,908 ha). By summing up the areas of the most frequent habitat types of the vegetation subregions, it became evident that the grasslands, ploughed in the past 15 years, are among the first five most spacious habitat types in all subregions.

Restricted access

In this paper we present an implementation of the natural capital index (NCI), a highly aggregated policy-relevant biodiversity indicator for Hungary, based on the MÉTA database, a detailed field-based vegetation database with a habitat quality attribute. To this end, we introduce two different weighting schemes for the field-estimated MÉTA values, both rooted in the concept of ecosystem services: a linear “equal steps” (NCI lin ) and an exponential (NCI exp ) weighting scheme. The natural capital index of Hungary and its physical geographical regions are calculated and presented from both aspects. The national NCI lin is 9.9% (indicating an overall 90% loss in the availability of the major supporting ecosystem services), and NCI exp is 3.2% (indicating an even greater degree of loss in terms of the conservation of rare species). The geographical regions of Hungary exhibit considerable spatial variation, which reveals important information on their basic characteristics (e.g. agricultural potential) and land use history. As NCI can be calculated on any spatial scales from local to national, this indicator may become a useful tool for policy development and evaluation purposes, including environmental impact assessments (EIA) and strategic environmental assessments (SEI). However, due to several conceptual limitations (e.g. disregard for rarity, spatial structure and cultural values, questions of recency and repetition) NCI should not be regarded as a self-sufficient universal tool, and strategic decisions should be based on careful consideration of all potentially relevant factors.

Restricted access
Orvosi Hetilap
Authors:
Krisztina Marosi
,
Endre Horváth
,
Péter Nagy
,
Bernadett Köles
, and
Zsolt B. Nagy

Az utóbbi években megerősítést nyert a fizikai teljesítmény jelentős mértékű genetikai meghatározottsága. Emellett a sportoláshoz köthető sérülésekre és betegségekre való genetikai hajlamról is egyre nagyobb ismeretanyag áll rendelkezésünkre. A teljesítményt befolyásoló génpolimorfizmusok vizsgálata lehetőséget kínál a sportági kiválasztási rendszer fejlesztésére. A sportoló genetikai profiljának ismerete a jövőben lehetővé teszi a személyre szabott edzésprogram kidolgozását és ezáltal a teljesítmény potenciális növelését. A genetikai tesztek a jövőben fontos szerepet játszhatnak a sérülések és a betegségek genetikai kockázati tényezőinek szűrésében is. Orv. Hetil., 2012, 153, 1247–1255.

Open access

Experiments were carried out on the sperm cryopreservation of artificially induced eels. The effects of several extenders and two cryoprotectants on the motility of spermatozoa were investigated. The highest post-thaw motility was observed with the combination of Tanaka's extender and DMSO as cryoprotectant. Further dilution after thawing resulted in complete loss of motility in samples frozen in presence of DMSO while sperm frozen with methanol as cryoprotectant retained its motility after further dilution.

Restricted access