Authors:Ágnes Vehovszky, A. Kovács, Henriette Szabó, J. Győri and Anna Farkas
The responses of the snail central neurons (Helix pomatia, Lymnaea stagnalis) and the isolated Helix heart were characterized evoked by cyanobacterial extracts (Cylindrospermopsis raciborskii ACT strains) isolated from Lake Balaton (Hungary). The nicotinergic acetylcholine (ACh) receptors in the CNS (both excitatory and inhibitory) were blocked by the extracts of ACT 9502 and ACT 9505 strains and the anatoxin- a (homoanatoxin-a) producing reference strain of Oscillatoria sp. (PCC 6506), similar to the inhibitory effects of the pure anatoxin-a. The enhancement of the ACh responses by the ACT 9504 extract suggests additional, probably acetylcholine esterase inhibitory mechanisms. On the isolated Helix heart the crude ACT 9505 and PCC 6506 extracts evoked frequency increase and transient twitch contraction, opposite to the ACh evoked heart relaxation. Anatoxin-a similarly contracted the heart but did not increase its contration frequency. These data suggest the involvement of some non-cholinergic mechanisms, acting very likely by direct modulation of the electrical or contractile system of the isolated heart. Diversity of the effects evoked by the cyanobacterial extracts in the CNS and heart suggest pharmacologically different neuroactive components among the secondary metabolites of the cyanobacteria acting on both (anatoxin-a like) cholinergic and (unidentified) non-cholinergic receptors.
Authors:Ágnes Vehovszky, Henriette Szabó, A. Ács, J. Győri and Anna Farkas
(Artemia) nauplii was used to asses the toxicity of rotenone, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), MP+ (1-methyl-4-phenylpyridinium) and the effect of L-DOPA co-treatment with rotenone. Rotenone had a dose dependent effect on mortality (LC50: 0.37 ± 0.04 μM mean ± S E, n = 24), while MPTP and MP+ proved to be toxic in millimolar range (LC50: 0.21 ± 0.09 mM and 0.20 ± 0.08 mM, respectively, n = 4). L-DOPA (50–200 μM) co-treatment increased the survival of the rotenone-treated animals (LC50: 0.51 ± 0.23 μM, 1.03 ± 0.66 μM, and 0.76 ± 0.52 μM, respectively). In the whole body tissue homogenates of Artemia, sublethal (up to 0.3 μM) concentrations of rotenone increased the glutathione S-transferase (GST) activity by up to 50 about percent (LC50: 53.3 ± 6.8 nM/min/mg protein, against 34.7 ± 3.6 nM/min/mg protein, n = 4). Nauplii treated in 100 mM L-DOPA and rotenone together showed further increase of GST activity all across the range of rotenone concentrations. These results on Artemia nauplii show similarities with other animal models, when complex I inhibitors were tested. Biochemical measurements suggest a protective role of L-DOPA by increasing the GST activity as part of the intracellular defences during toxin-evoked oxidative stress.
Authors:J. Gál, Cs. Jakab, B. Balogh, T. Tóth and B. Farkas
The occurrence of a periosteal chondroma (juxtacortical chondroma) in an adult male
is documented for the first time. The chondroma developed near the right shoulder joint from the periosteal membrane, causing partial atrophy in the surrounding skeletal muscles. In the chondroma tissues widespread central necrosis and secondary calcium salt deposition were observed. Monomorphic chondrocytes were irregularly spread in the chondromucin matrix. The lizard had locomotor problems due to irritation of the periosteum and reduced movement of the bones constituting the shoulder joint caused by the chondroma.
Authors:C. Farkas, A. Hagyó, E. Tóth, J. Szabó and T. Németh
This study was carried out to evaluate the soil hydrophysical properties and soil water regime of two irrigated maize fields in order to support irrigation planning and management. The experimental sites were located in Mezohegyes (MZH) and Hódmezovásárhely (HMV) in SE Hungary. In total 11 monitoring stations were chosen, using information from a previously developed, GIS-based agro-geoinformation system. In 2003 and 2004 soil sampling and in situ measurements were performed to determine the soil hydrophysical properties and soil water content dynamics. The hydraulic conductivity of the topsoil was evaluated from double ring infiltrometer measurements. A previously calibrated TDR 300 instrument and a 3T-M capacitance probe were used for quantifying the soil water content. Both types of equipment were found to require calibration and testing under field conditions before use. It was concluded that the study fields could be considered relatively homogeneous in relation to both soil hydrophysical properties and soil water regime. Thus, monitoring stations established for one or two carefully selected soil profiles could provide enough data to ensure proper decisions on irrigation. The results indicate that the soil management system and irrigation strategy used in the experimental fields ensured satisfactory soil and soil moisture conditions.
Authors:H. G. Daood, R. Tömösközi-Farkas and J. Kapitány
In the present work, bio and conventional forms of spice red pepper were analysed using various high performance liquid chromatographic (HPLC) systems for their carotenoid, tocopherol and vitamin C contents. The carotenoid pigment was fractionated into free xanthophylls, monoesters, carotenes and diesters with newly developed reversed phase HPLC, while a-, b- and g-isomers of vitamin E were separated by normal phase chromatography. Ion-pair chromatography on a C-18 column provided good separation and quantification of vitamin C. The peppers included new resistant varieties and hybrids that are essential for bio-production. It was found that crossing new disease-resistant varieties such as Kaldom and Kalorez with susceptible ones such as Rubin and SZ-20 produced resistant hybrids that contained higher levels of quality components compared to the parents, particularly when grown and cultivated under organic farming conditions.
Authors:J. Farkas, É. Andrássy, Z. Formanek and L. Mészáros
A bioluminescent derivative of Bacillus subtilis containing a plasmid encoding a luxAB fusion under control of a vegetative promoter and gives bioluminescence upon addition of an exogenous long-chain aldehyde has been used as test organism. Its spore populations have been produced and their heat- and radiation survival curves established. Heat-sensitization effect of pre-irradiation of spores was proven not only by colony counting but also with differential scanning calorimetry. Under a linearly programmed temperature increase, the heat destruction of spores surviving 2.5 kGy gamma irradiation resulted in at a few centigrade lower temperature than that of untreated spores. Heat denaturation endotherms in the DSC-thermogram of irradiated spores were shifted to lower temperatures as well. Comparative turbidimetric, luminometric and phase-contrast microscopic studies of untreated, heat-treated and irradiated spore populations showed that the kinetics of germination and the light emission during germination of radiation-inactivated spores were the same as those of untreated spores, revealing that the pre-formed luciferase enzyme packaged into the spores during sporulation remained intact after an irradiation dose causing 90% decrease in number of colony forming spores. Therefore, in contrast to heat-treated spores, the initial bioluminescence reading upon germination of irradiated spores does not reflect the viable count of their population.
Authors:K. Horváth, É. Andrássy, M. Korbász and J. Farkas
Experimental batches of chilled cutlets of pork have been stored aerobically and surface growth of bacteria was determined by standard aerobic spread-plate counts, and colony counts of pseudomonads on Cetrimid Agar simultaneously with detection times of respective stomached samples in triplicate using a Malthus Microbiological Analyzer at 30 °C, applying general impedance broth and
impedance medium, respectively. To study the effects of storage temperature on growth of spoilage bacteria, numerous samples were kept in successive experiments at 4, 8 or 12 °C. Parameters of the bacterial growth curves were estimated by curve fitting of the colony counts by DMfit programme package of the ComBase softwares, using Baranyi’s dynamic growth model. Linear correlations were found between the respective colony counts and the conductimetric detection times observed in periodic investigations during storage. According to these calibrations, the conductimetric method at 30 °C incubation is able to assess within 8 h whether a sample of pork cutlets contains greater or less than 10
of psychrotrophic spoilage bacteria.
Authors:K. Horváth, Zs. Seregély, É. Andrássy, I. Dalmadi and J. Farkas
Experimental batches of chilled boneless slices of pork meat have been stored aerobically in sterile Petri dishes and total aerobic plate counts (TAPC) and sensorial observations were made periodically during storage to monitor bacterial growth and apparent deteriorative changes at 4, 8 and 12 °C, respectively. Near infrared spectroscopy (diffuse reflectance) measurement was performed on replicate meat samples in the wavelength range of 1000–1800 nm. Second derivative and multiplicative scatter correction were performed on the spectra as data pre-treatments. Principal component analysis (PCA) and canonical discriminant analysis (CDA) were used for observation of discrimination of the samples due to loss of freshness and onset of bacterial spoilage as a function of the storage time. The percentage of correctly classified samples decreased somewhat by increasing the storage temperature. Partial least squares (PLS) chemometric model was developed to predict and quantify bacterial loads from the scatter corrected 2nd derivative spectra. PLS evaluation (predicted versus measured TAPC values) — when bacterial counts at all sampling days and storage temperatures were taken into account — resulted in a correlation coefficient of 0.977, and a root mean square error of prediction (RMSEP) 0.438 log colony forming units/g. These preliminary results indicate the potential of utilising near infrared diffuse reflectance spectroscopy in combination with multivariate statistical methods to monitor loss of freshness and detect bacterial spoilage of meat samples rapidly before deleterious microbial changes become apparent. However, much larger number of samples should be studied to ascertain properly the prediction power of the spectroscopic method.
Authors:J. Farkas, É. Andrássy, A. Simon and L. Mészáros
A recombinant Bacillus subtilis strain containing a plasmid encoding a luxAB fusion, which gave bioluminescence upon addition of an exogenous long-chain aldehyde as substrate for the endogenous luciferase enzyme, was used as test organism. Its populations were treated with 300 MPa for 20 min, or 600 MPa for 20 min at around room temperature, and this treatment is foreseen as a quality-friendly, non-thermal pasteurisation of foods. Besides the estimation of viable cell counts, the extent of pressure-induced germination and post-process development were investigated by phase-contrast microscopy, turbidimetry and luminometry. Increased heat sensitivity of pressurized spore populations was observed both by viable cell counting during a linearly programmed elevation of temperature and a simultaneous differential scanning calorimetry. This was related to pressure-induced germination of spores, although a small fraction remained ungerminated. The luciferase pool built into the spores during their formation seemed to have withstood pressurization. Spore germination was accompanied by the emergence of bioluminescence which also indicated sensitively the characteristic changes of metabolic activity running parallel with the development of untreated cell populations and that of the survivors of the hydrostatic pressure treatments when the cells were incubated in a nutrient broth.
Authors:G. Farkas, J.M. Rezessy-Szabó, F. Zákány and Á. Hoschke
Fermentation trials were conducted in all-malt wort with mixed cultures of SaccharomycescerevisiaeWS 34/70 and one of two non-Saccharomycesyeast strains: Saccharomycodesludwigiiand Torulaspora delbrueckiiDSM 70607. Interactions were observed between the two yeasts during the alcoholic fermentation process started with eight different initial cell ratios ranging from 1:1 to 1:20 (Saccharomyces yeast : non-Saccharomyces yeast). Composition of the medium greatly affected the cell yield, degree of attenuation and ethanol concentration due to the maltose-negative characteristic of the non-Saccharomycesyeast strains. Starting cell ratios had less effect on the outcome of the fermentation experiments. S. cerevisiaelimited the growth of T. delbrueckiito a great extent, overgrowing it in the course of fermentation. On the other hand, S. cerevisiaedid not grow as dynamically in mixed culture with S. ludwigiias the composition of the medium would have suggested.