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E. Vives: Coleoptera-Cerambycidae, Fauna Ibérica, Vol. 12., Museo National de Ciencias Naturales, Consejo Superior de Investigaciones, Madrid 2000, p. 715 L. Bos: Plant Viruses, Unique and Intriguing Pathogens- A Textbook of Plant Virolgy, Bachuys Publishers, Leiden 1999, p. 358

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Shell eggs have been irradiated with increasing radiation doses in the 0.5-3.0 kGy dose range and various non-microbiological changes, important from the point of view of consumer quality, have been estimated. Dose-dependent changes in the flow behaviour of egg white and brittleness of the yolk membrane in broken eggs, sensorial parameters of the raw and soft-boiled eggs, whippability and foam stability of the egg white were observed. Considering that a minimal dose of 1.5 kGy would be required for radiation inactivation of salmonellae and other, non-pathogenic bacteria, the quality of irradiated eggs upon such gamma radiation dose would not be equal in all parameters to those of the fresh shell eggs, however, changes in sensorial and functional properties at this dose level may be still acceptable, mainly for risk population and some industrial use.

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Neuropteroidea communities were studied near Budapest (Nagykovácsi) in an abandoned, mixed orchard and its neighbouring environment: a shrub community without a closed canopy; a shrub level of the canopied oak forest by using Malaise traps. In the open shrub verge of the orchard larger, and in the oak forest more diverse Neuropteroidea community developed than in the other investigated habitats. The Neuropteroidea communities studied did not show stable compositions in the investigated habitats and years.

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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.

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The effect of explant type (immature vs. mature embryos) and two auxin types (2,4-dichlorophenoxyacetic acid vs. Dicamba) on the callogenesis and plant regeneration ability of 26 wheat cultivars was studied. In general, the callus induction, plant regeneration and shoot formation frequencies were higher in mature embryo-derived cultures as compared to immature ones on media originally developed for mature wheat embryo cultures. In both culture types, the auxin Dicamba was found to be more efficient, especially when mature embryos were cultured. The separation of means using Duncan’s multiple range test revealed the best in vitro response, in terms of the frequency of callus regeneration, in the cultivar Astella for both immature and mature embryo cultures. This cultivar gave very promising results, suggesting that it could be used in the future for further tissue culture investigations and as a donor material for genetic transformation experiments in wheat. Correlation analyses revealed significant similarities between the evaluated parameters within each group (immature and mature embryo-derived cultures). However, there were no significant correlations between these two groups for most of the parameters. This suggests that the mechanism of plant regeneration in the two in vitro regeneration systems (mature vs. immature embryo culture) may be different enough to hamper the development of an optimal plant regeneration protocol for use in both systems.

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Laboratory batches of fresh tomato juices were treated in several experimental trials by high hydrostatic pressure alone or in combination with various concentrations of oregano, thyme or dill seed oils. Lactic acid bacteria formed the dominating component of the spoilage microbiota during post-processing storage at 15 °C causing spoilage of the untreated samples within 4 days. One tenth of a percent oregano or thyme oils at least doubled the microbiological shelf life, while their respective concentrations of 0.5% alone, or 400 MPa 5-20 min high hydrostatic pressure treatment alone resulted in microbial stability for at least two weeks. Two hundred MPa for 10 min resulted only in an approx. 3 days delay of spoilage, whereas 0.1% thyme oil increased the efficiency of this moderate UHP-treatment, resulting in a microbiologically stable product for at least 3 weeks at the storage temperature applied.

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Facing contrasting light regimes during a vegetation season and depending on canopy position, physiological plasticity of leaves is vital for tree species to sustain the optimal ratio between the benefit of carbon assimilation and the costs of photoprotection in a given leaf. We tested the seasonal adjustment of sun and shade leaf photochemistry of sessile oak (Quercus petraea (Matt.) Liebl.) to changing light environments by parallel investigation of the meteorological conditions, photosynthetic pigment content, PSII quantum efficiency and excitation energy quenching. Sun and shade leaves got adapted to their prevailing light regimes till mid of May. High LMA was a favourable trait in avoiding water loss and decreasing photoinhibition in both flushing and sun leaves, while low LMA optimized the light absorbing leaf surface in the lower canopy layer. Partitioning of excitation energy dissipation pathyways that is PSII photochemistry-Y(II), regulated-Y(NPQ) and non-regulated-Y(NO) quenching changed significantly during leaf ontogeny and with the position of leaves in the canopy. At 800 μmol m−2 s−1Y(II) < Y (NO) < Y (NPQ) was characteristic to early developmental stage of leaves from both canopy layers and to mature shade leaves, and Y(NO) < Y (II) < Y (NPQ) to mature sun leaves but the magnitude of Y(NPQ) and violaxanthin cycle activity differed in different canopy positions.

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In this study sap flow dynamics of mature sessile oak trees (Quercus petraea) in a marginal sessile oakturkey oak forest was investigated in 2009. That year spring was dry without significant rain in April and May and the driest month was August. Due to the extreme weather conditions the volumetric soil water content (SWC) of upper 30 cm was low on experimental days in May (0.13–0.14 cm3 cm−3) but it reached the lowest value in August (0.08 cm3 cm−3). Sap flow was measured in a dominant and a co-dominant tree by heat dissipation method from 26 March till 30 October. In the present paper several three-day long periods of the continuous seasonal recordings were chosen to represent the effects of typical weather conditions and different stages of canopy development on sap flow dynamics. The daily maximum sap flow density values of dominant and co-dominant trees were similar (0.30–0.32 cm3 cm−2 min−1) in moist period (July). Rains and transient increase of SWC after proceeding drought resulted in change of diurnal course of sap flow in experimental days of July. In this period dominant trees also showed considerable sap flow (0.19 cm3 cm−2 min−1) during night hours and short sap flow peaks in early morning (6:00 to 8:00 a.m.) indicating the refilling of desiccated tissues. After the progressive drought in August the daily maximum sap flow density decreased to 0.07 cm3 cm-2 min-1 in dominant tree and to 0.12 cm3 cm−2 min−1 in the co-dominant. Both trees exhibited gradual stomatal closure from morning hours.

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Cereal Research Communications
Authors:
J. Bányai
,
P. Szűcs
,
I. Karsai
,
K. Mészáros
,
Cs. Kuti
,
L. Láng
, and
Z. Bedő

A total of 96 winter wheat ( Triticum aestivum L.) cultivars registered in Hungary were analysed using 15 wheat microsatellite markers located on different chromosome arms. Analyses revealed 91 SSR alleles with sizes ranging from 123–239 base pairs. The total number of alleles per locus ranged from 2 (Gwm664 and Gwm415) to 11 (Gwm219) with an average number of 6.1. The polymorphic information content (PIC) values ranged from 0.06 to 0.85 with an average number of 0.60 for all markers. Several markers included allele sizes characteristic of a single or a small number of cultivars. At most 9 SSR markers were required to distinguish the 96 cultivars, so the simple sequence repeats could serve as a relatively cheap, rapid method for identifying winter wheat cultivars.

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Acta Alimentaria
Authors:
Á. Koncz
,
L. Mészáros
,
J. Farkas
,
K. Pásztor-Huszár
,
R. Helt
, and
N. Lechner

Thermal and HHP treatments were compared. We established that the applied HHP treatments reduced the total cell count more significantly than thermal treatments. For example, the 10 min 600 MPa/10 min HHP treatment was equivalent to about 10 min thermal treatment at 70 °C. This combination of temperature and time is not used in the pasteurisation practice of the dairy industry. The various thermal treatments reduce the phosphatase enzyme activity to between one-third and one-hundredth of the original activity. The HHP treatments yielded similar results. Six hundred MPa pressure caused 10 to 70% decrease in the enzyme activity, while 700 MPa pressure led to a decrease of one log cycle.In the second year we tried to investigate the kinetics of the effect of HHP treatment. The 5, 10, 20, 40 min holding times were systematically applied in the range of 400 to 700 MPa. According to the results, 600 and 700 MPa HHP treatments effectively assured a decrease in the total cell count and the alkaline phosphatase enzyme activity. No organoleptic changes occurred.

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