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  • Author or Editor: P. Horváth x
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Authors provide a 6-year study about aspects of development of Cameraria ohridella and its parasitoids in different leaf types of horse-chestnut trees. Investigations were carried out near Hédervár, North-West Hungary between 1999 and 2004.It was ascertained that in large leaves at low foliage levels as well as in large leaves exposed to direct sunlight developed more moths than in other leaf types of equal quantity (i.e. equal number of leaflets). On the other hand, there were not considerable differences between shaded and sun-exposed leaves in this regard if their quantity is measured in grams. Moreover, comparing the numbers of hatched moths per unit leaf weight, the values for minute leaves were the highest. The differences were explained on the basis of diverse microclimatic conditions in the mines, height preference of the moth or variations in dry weights per unit leaf area.Parasitism of Cameraria ohridella showed significant yearly differences between canopy levels and a tendency of changes during the years. Parasitism was higher in shaded than in sun-exposed leaves. Lowest values were found in minute leaves among all leaf types investigated what was explained with a presumed foraging behaviour of the parasitoids.Structure and species constitution of the parasitoid community and its changes in time are discussed in different leaf types. Temporal changes of several characteristics found in different leaf types refer to an adaptation process of the horse-chestnut leafminer.

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The horse-chestnut leafminer is a new pest which was established in North-West Hungary ca. 10 years prior to these investigations. Due to the very limited time, there are relatively few studies on the parasitoid community of the moth and its connection with the leafminer host. Authors used twig-isolators to find out which larval/pupal instars are mostly parasitized and by which chalcidoid species. They also made an attempt to calculate density curves of different developmental stages of the moth and to compare them with flight curves of the parasitoids. Experiences indicated that 4-week-old larval (pupal) instars were parasitized to the highest degree. The most frequent parasitoids were Pediobius saulius and Pnigalio agraules . Statements about a poor synchronization between moth and parasitoids were confirmed but possibility of a shift in swarming times on location was suggested. Different methods to calculate rate of parasitism were compared and evaluated.

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The aim of our study was to investigate the susceptibility of some Chenopodium species (Chenopodium album, C. glaucum, C. berlandieri, C. ugandae) to six viruses (Alfalfa mosaic virus, Cucumber mosaic virus, Obuda pepper virus, Potato virus Y, Sowbane mosaic virus, Zucchini yellow mosaic virus). Fourteen plants of each species were mechanically inoculated and virus susceptibility was evaluated on the basis of symptoms and back inoculation. A series of new host-virus relations were determined.

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In this review results are summarized regarding the effect of virus infection on the physiological processes of weeds. Through several host-virus model relations the biomass and seed production, seed viability and germination, nutrient uptake, drought-resistance and photosynthetic pigment content of healthy and virus infected plants were compared. Because of their broad host range and high genetic variability viruses cannot be used for biological weed control. It was concluded that viruses unfavourably can influence physiological processes of weeds. Therefore, they may contribute indirectly to the reduction of competitive ability and population of weeds.

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Acta Biologica Hungarica
Authors: Á. Horváth, P. Sántha, V. Horváth, Nóra Török, I. Nagy, G. Jancsó, Cs. Vágvölgyi and F. Somogyvári

A new, rapid method is described which permits the genotyping of genetically modified animals from a microlitre volume of whole blood samples via one step polymerase chain reaction amplification. The major advantage of the presented method is the exclusion of a DNA preparation step, which significantly reduces the time expenditure and work load of the genetic testing. Pilot studies indicate, that this method is efficient and applicable also on tissue biopsies and larger amount of blood providing a rapid and reliable new technique over conventional genotyping approaches.

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In the second part of our study we have examined the effect of Tobacco mosaic tobamovirus (TMV) infection on the germination, seed trans­mission, seed viability and seed production of S. nigrum. Transmission of TMV by seeds of S. nigrum was 0.3%. Average seed production of the virus infected plants was reduced by 52%, as compared to the healthy control, and TMV infection also delayed generative development. Virus infection did not influence the germination of the seeds. Viability of seeds derived from ripened (blue-black) berries, was significantly reduced by TMV infection.

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Susceptibility of 33 Lycopersicon species and intra-specific taxa to 6 viruses such as U/246 strain of Cucumber mosaic virus (CMV), Pepino mosaic virus (PepMV), Potato virus X (PVX), NTN strain of Potato virus Y (PVYNTN), Tobacco mosaic virus (TMV) and Tomato mosaic virus (ToMV) were studied. Inoculated plants were tested for susceptibility on the basis of symptoms, serological reactions (DAS-ELISA) and back inoculation. All tested plants were susceptible to PepMV, PVX, TMV and ToMV. However, Lycopersicon esculentum Mill. convar. parvibaccatum Lehm. var. cerasiforme (Dun.) Alef.s.l., L. peruvianum (L.) Mill. and L. hirsutum Humb. et Bonpl. were extreme resistant (immune) to PVYNTN. L. esculentum Mill. convar. infiniens Lehm. var. flammatum Lehm., L. esculentum Mill. convar. fruticosum Lehm. var. speciosum Lehm. and L. esculentum Mill. convar. infiniens Lehm. var. validum Bail. showed extreme resistance to CMV-U/246. The other 30 species and intra-specific taxa were susceptible to CMV-U/246. New compatible and incompatible host-virus relations have been reported. The extreme resistant Lycopersicon intra-specific taxa could be used as resistance sources in tomato breeding.

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Acta Biologica Hungarica
Authors: Eszter László, P. Kiss, Gabriella Horváth, P. Szakály, Andrea Tamás and Dóra Reglődi

Pituitary adenylate cyclase activating polypeptide (PACAP ) is a multifunctional neuropeptide occurring in the nervous system as well as in the peripheral organs. Beneficial action of PACAP has been shown in different pathological processes. The strong protective effects of the peptide are probably due to its complex modulatory actions in antiapoptotic, anti-inflammatory and antioxidant pathways. In the kidney, PACAP is protective in models of diabetic nephropathy, myeloma kidney injury, cisplatin-, gentamycin- and cyclosporin-induced damages. Numerous studies have been published describing the protective effect of this peptide in renal ischemia/reperfusion. The present review focuses on the ischemia/reperfusion-induced kidney injury and gives a brief summary about the results published in this area.

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Acta Biologica Hungarica
Authors: Zsuzsanna Pluhár, Marianna Kocsis, Anett Kuczmog, S. Csete, Hella Simkó, Szilvia Sárosi, P. Molnár and Györgyi Horváth

Chemical and genetic differences of twenty taxa belonging to four Thymus species were studied in order to determine whether molecular characters and essential oil components could be used as taxonomic markers and to examine the correlation between them. Plant samples, representing different taxa and geographic regions, were collected from experimentally grown populations. Essential oil samples were analysed by GC/MS and cluster analysis of volatile composition resulted in segregation of thymol chemotypes from sesquiterpenic ones. Thymol was characteristic for all the populations of Thymus glabrescens and T. pannonicus as well as for certain taxa belonging to T. praecox and T. pulegioides. Sesquiterpenes occurred in only two taxa of T. glabrescens, in each sample of T. praecox and in three taxa of T. pulegioides. Plant samples were analysed by random amplified polymorphic DNA (RAPD). The obtained dendrogram revealed high gene diversity. The 13 primers resulted 114 polymorphic RAPD bands, and the average percentage of polymorphism was 80.8%. The RAPD dendogram showed separation neither at interspecific nor at interpopulational levels. Therefore, further specific molecular studies involving more taxa are suggested. Partial correlation have been found between molecular and chemical assessments.

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Trap designs baited with the synthetic sex pheromone have been optimized for trapping of the western corn rootworm Diabrotica v. virgifera LeConte (Coleoptera: Chrysomelidae) (WCR), which has recently been introduced into Europe. The best trap design proved to be the sticky “cloak” trap (code name “PAL”), which catches only males, and is being used in many countries of Europe for detection and monitoring the spread of the new pest. Preliminarily the range of attraction (as defined by Wall and Perry, 1987) of the pheromone traps was estimated to be <10 m. The performance of yellow sticky plates (used by others for monitoring of the pest) was insignificant as compared to the activity of the pheromone baited traps, and yellow colour had no discernible effect on catches in pheromone traps. The known floral lure of WCR containing 4-methoxy-cinnamaldehyde and indole proved to be active also towards the population in Europe, attracting both females and males. Yellow colour slightly increased catches by the floral lure, hence a yellow sticky “cloak” trap has been developed (code name PALs). Pheromone baited PAL traps caught a total of about 4 times more beetles than the floral baited PALs, which latter however appeared to be preferentially active for females. When placed into the same trap, the pheromonal and floral lures did not interfere with each other's activity.

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