Search Results

You are looking at 1 - 10 of 30 items for

  • Author or Editor: L Mészáros x
  • Refine by Access: All Content x
Clear All Modify Search

Using laboratory experiments, the daily activity patterns of 16 Neuroptera species (6 Chrysopidae, 2 Coniopterygidae, 3 Hemerobiidae, 3 Myrmeleontidae, 1 Mantispidae, 1 Ascalaphidae) were studied by the authors. The results of the experiments were described by activity diagrams and were categorized into Duelli-type flight activity pattern. During the study, 14 species showed carnea type of nocturnal activity. Mantispa styriaca proved to belong to hypochrysodes type which is active at daytime. The daily activity pattern of Libelloides macaronius differs from the hypochrysodes type due to its strong preference of UV radiation; therefore it is described as a separate libelloides type.

Restricted access

Studying ascalaphid materials from Thailand, Laos and Pakistan the authors determined specimens which belonged to the genus of Nousera.  In this paper the redescription of the genus of Nousera and its type species, Nousera gibba Navás, 1923 can be found. Besides Nousera herczigi, a new species from Pakistan is also described. With altogether 23 figures. In the end the species of Nousera were revised and found that Nousera furcifer (Van der Weele, 1909) does not belong to the genus of Nousera. As its original generic name of Pseudoptynx Van der Weele, 1909 is a homonym, a new name (nomen novum) has to be given replaced such as Ascapseudoptynx furcifer (Van der Weele, 1909).

Restricted access

The present study gives a description of two new genus belonging to Ascalaphini tribus according to the classification of Ascalaphinae Lefébvre, 1842 [=Schizophthalminae Weele (1908)]: the Horischema gen. n. and Perissoschema gen. n. It also describes some of their species, Horischema ronkayorum sp. n. and Perissoschema evae sp. n. from the area of the Himalayas, Pakistan, and Nepal. Key for all genera of the tribus is given. With 8 photos.

Restricted access

In the present paper a description of Stylascalaphus fabiani sp. n., a new taxon from Pakistan, is given with illustrations.

Restricted access

In this study the Ptyngidricerus Van der Weele, 1908 genus has been revised and in the course of this 2 new genera and 4 new species are described. The description of the new genus was made possible apart from the male samples, the females (P. albardanus) which were recorded and supplement of the description based on damaged specimens (P. ira­nensis) earlier enabling the evaluation of their taxonomic status. The following species belonging to Ptyngidricerus genus: Ptyngidricerus albardanus albardanus (McLachlan, 1891), Ptyngidricerus albardanus pterostigmatus Alexandrov Martynov, 1926, Ptyngidricerus pseudo­albar­da­nus sp. n. Ptyngidricerus persepolisensis sp. n. and Ptyngidricerus sen­da­nensis sp. n. from Iran and Ptyngidricerus pakistanensis sp. n. from Pa­kistan. Apart from describing the new species the authors present a des­cription of the female Ptyngidricerus albardanus albardanus (McLachlan, 1891) which has so far not been known according to the literature on this species. The earlier described species were combinated on the basis of their genitalia and external morphological characteristics in new genus: Iranoidricerus iranensis (Kimmins, 1938) and Omanoidri­cerus venustus (Tjeder and Waterston, 1977). The illustration of the female and male genitalia of Iranoidricerus iranensis Kimmins, 1938 is also presented. On account of sexual dimorphism a key is given for identification of the female and male specimens with 25 figures.

Restricted access

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.

Restricted access

The microbiological spoilage of foods depends on the initial microbiological contamination and some factors which influence the growth of microorganisms. Therefore, reducing the initial cell count is necessary for both extending shelf-life and improving food safety. Physical, chemical and combined treatments serve this purpose. In these experiments, the effect of trisodium phosphate dipping (0-15% solutions) was studied. Chicken wings were used, which after dipping (1 min) in the solution were packed in PE-PA-PE pouches and stored at 4 °C. Aerobic mesophilic (Nutrient Agar, Merck), pseudomonad (Pseudomonas Selective Agar, Oxoid), and Enterobacteriaceae counts (VRBD Agar, Merck) were determined by Spiral Plate Technique at 30 °C incubation temperature. Effect of 3.8, 5.7, 7.6% trisodium phosphate dipping solutions was studied as a function of storage time. Immediately after treatment, total colony count was reduced by maximum 1.5 log cycles. Pseudomonads were the most sensitive. One day after treatment with these low concentration solutions, the colony count was reduced by 2 log cycles. Na3PO4concentration higherthan 7.6% practically did not result in higher effectivity. The growth rate and maximum cell count of surviving fraction were estimated as a function of trisodium phosphate concentration. It can be concluded from fitted survival curves that immediately after treatment the initial viable cell count was reduced and the critical spoilage level (107g-1) has been reached 2-3 days later than in case of the untreated samples, i.e. the shelf-life was extended.

Restricted access

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.

Restricted access

Suspensions of a bioluminescent (luxAB) transformant of Listeria monocytogenes in pH 7.0 phosphate buffer were pressurised and the effect of the pressure treatment was monitored by plate counting. When the bacteria were suspended in NaCl- and nisin-free buffer the number of colony forming units (CFU) decreased by 3 and 6 log cycles after 300 MPA for 10 and 30 min, respectively. Supplementing the plating medium with 5% NaCl did not influence the colony forming capacity of non-pressurised cells, however, CFU of residual populations after respective treatments of 300 MPa for 10 and 30 min were reduced by a further 2 and 3.5 log cycles in case of salt containing plates. Nisin-addition to the plating medium caused less than one log unit decrease in the CFU of the non-pressurised population. However, the CFU of 10 min-pressurised sample was 4 log cycles less in the nisin-containing plates than in the nisin-free ones, whereas no colonies were formed in the nisin-containing plates even when 1 ml was inoculated from the originally 1010 CFU/ml population after 300 MPa for 30 min. The luciferase activities (bioluminescence intensities) decreased concomitant with the reduction of the viable cell counts, however, they were approx. 0.6-0.8 log units less in the presence of 5% NaCl in the pressurised suspension than those expected from the previously established linear correlation between the logarithmic light outputs and the logarithmic viable cell counts.

Restricted access

The effect of vernalization response and photoperiod sensitivity on reproductive fitness and agronomic traits was examined in a group of 16 H. spontaneum accessions and 8 H. vulgare cultivars in controlled environments. The whole range of plant developmental and agronomic traits was determined by vernalization. The reproductive fitness was severely impaired when the vernalization requirements of the plants were not saturated. Variation in the magnitude of vernalization response significantly correlated with several traits. A larger decrease in reproductive tiller number, average seed number and consequently final grain yield was more characteristic of accessions with a greater vernalization response. When the vernalization requirement was met, long photoperiod enhanced the fitness of the plants and resulted in larger yield and yield components, irrespective of the genotype, while short photoperiod acted as a limiting factor for all these traits. There was, however, a difference in the reaction type of wild and cultivated genotypes due to their different plant strategies.

Restricted access