Authors:L. Horváth, Cs. Székely, Zs. Boczonádi, E. Mészáros, M. Bercsényi, B. Urbányi, and T. Müller
European eel is a catadromous fish species, which means that after living in freshwater premature individuals adapt to sea water, and migrate to the Sargasso Sea for spawning. Although male eel can be sexually matured even in freshwater, to date, it was believed that female eel can be matured only in seawater. Here we show that the process of sexual maturation may be induced in freshwater by treating female eels with carp pituitary (GSI = 9.87±1.55%). It is thus proposed that seawater condition is not an obligatory environment for stimulating gametogenesis and for artificial maturation of the European eel in neither gender.
Authors:Zs. Bakacsi, L. Kuti, L. Pásztor, J. Vatai, J. Szabó, and T. Müller
An attempt is outlined for the compilation of an integrated and harmonized stratified soil physical database serving hydrologic modeling, as the basis of estimating soil hydraulic parameters in the unsaturated zone. Due to the appropriate spatial and thematic resolution and data processing status, the Digital Kreybig Soil Information System (DKSIS) and Hungarian Agrogeological Database (HAD) were chosen as pedological and agrogeological data sources for describing the soil physical properties in the unsaturated zone. The DKSIS contains legacy soil data (as hy, pH, salt, OM, CaCO
content, etc.) in finely stratified resolution (3–5 soil layers within 1.5–2.0 m), but lacks particle size data. HAD has a coarser stratification (8–15 layers within 8–10 m) with detailed particle size data. The five-cleft FAO texture classification can serve as an interface in their joint application. The particle size and hy data pairs from the existing Hungarian Soil Monitoring (TIM) network made it possible to define the relation between FAO texture class vs.
value, and based on the HYPRES database each FAO texture class can be characterized by typical Mualem-van Genuchten parameter sets (Wösten
et al., 1999). The compiled, harmonized database characterizes the distinguished soil and sediment layers – with a thickness of at least 10 cm – for a 690 km
large model area, describing their thickness and texture classes to the depth of the permanent groundwater level, in every single square kilometer cell of the model area. The compiled database is indispensable in the model simulation based analysis of regional water management problems like drought, flood and inland inundation.
Authors:G. Szabó, T. Müller, M. Bercsényi, B. Urbányi, B. Kucska, and Á. Horváth
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.
Authors:T. Müller, F. Baska, F. Niklesz, P. Horn, B. Váradi, and M. Bercsényi
The artificial induction of sexual maturation of European eel males was carried out by using weekly hCG administrations. Histological pictures showed that the testis tissues developed and regressed naturally and no pathological changes took place under the conditions of artificial rearing in freshwater. According to light and electron microscopic investigations the morphology and motility of the spermatozoa of males kept in freshwater proved to be similar to those in seawater. The authors suppose that freshwater rearing of males is not a barrier factor in the artificial propagation of European eels.
Authors:T. Müller, T. Molnár, A. Szabó, E. Yamaha, Éva Járási, M. Bercsényi, A. Specziár, B. Urbányi, and R. Romvári
The present study aimed in vivo tracking of maturation of male eel by computed tomography (CT). Additionally, individually monitored testes sizes were correlated with the conventionally used external maturity indicators (i.e. eye and nose indexes) in order to test and improve their usefulness at individual level. Testes could be clearly identified with the CT from the end of the third week of hCG administration routinely used to induce maturation in fish. The volume of testes increased exponentially during hormone treatment, and by the end of the sixth week of maturation procedure all males produced motilable spermatozoa. Present results prove that testes size can noninvasively be monitored with CT from maturity level where testes size rich 3000 mm3 volume. Eye and nose indexes are in close correlation with testes volume and thus can also be effectively used to monitor maturaty level of male eel, but preferably only at stock level. However, due to their high individual variability, these indexes can be applied only with caution at individual level and should be supplemented with other noninvasive techniques such as CT.
Authors:P. Schuster, T. Müller, A. Vos, T. Selhorst, L. Neubert, and E. Pommerening
A comparative study of immunogenicity and efficacy of the oral rabies virus vaccine SAD P5/88 in raccoon dogs and foxes was conducted. The raccoon dogs received 10 (n = 6), 106.3 (n = 6) or 105.7 FFU SAD P5/88 (n = 5) by direct oral application, and subsequently all animals seroconverted. The foxes received 107.2 (n = 4), 106.2 (n = 4), 105.2 (n = 4) and 104.2 FFU SAD P5/88 (n = 5) by the same route. On days 106 and 196 post vaccination 10 raccoon dogs and 16 foxes were challenged with a relevant street virus, respectively. All 10 raccoon dogs vaccinated with 106.3 (n = 5) or 105.7 FFU SAD P5/88 (n = 5) survived the challenge, whereas all control animals (n = 5) died of rabies. Two foxes vaccinated with 104.2 FFU and one fox vaccinated with 105.2 FFU died of rabies on day 7, 17 and 12 post infection, respectively. Also all control foxes succumbed to rabies. Our findings demonstrate that SAD P5/88 is not only an effective vaccine for oral vaccination of foxes but also for that of raccoon dogs.
Authors:Blanca Rojas de Gáscue, José Luis Prin, Gilma Hernández, Enrique M. Vallés, Arnaldo T. Lorenzo, and Alejandro J. Müller
The application of the Successive Self-nucleation and Annealing (SSA) thermal fractionation technique can yield detailed information of the structural changes induced in linear polyethylene by irradiation. The production of tertiary carbons during the crosslinking reactions can be equivalent to the structural heterogeneity present in branched polyethylenes since in both cases interruption of the linear crystallizable sequences occurs, and these are structural differences that can be easily detected by thermal fractionation. We demonstrate how correlations between melting point and short chain branching content employed for branched polymers can be useful to characterize the distribution of chain heterogeneity produced by crosslinking. As the radiation dose is increased and the crosslinking content also increases, the distribution of chain heterogeneity gets broader as detected by SSA. When the results are coupled with morphological observations made by transmission electron microscopy, valuable information on the morphological changes produced by crosslinking can also be ascertained, since the distribution of lamellar thicknesses substantially broadens with crosslinking. Such a broad distribution can also be predicted from SSA by simple calculations performed employing a modified version of the Gibbs–Thomson equation and is expected on the basis of random crosslinking reactions.
Authors:Krisztina Rusai, A. Prokai, C. Juanxing, K. Meszaros, B. Szalay, K. Pásti, V. Müller, U. Heemann, J. Lutz, T. Tulassay, and A. Szabo
Previous experimental data suggest that steroids might have protective effects during hypoxic/ischemic injury of various organs. In this study, the association between dexamethason (Dexa) treatment and the anti-apoptotic SGK-1 was tested in ischemic renal injury. In vitro, HK-2 cells were exposed to 24 h hypoxia, and the effect of Dexa incubation on SGK-1 expression / activation and on cell death was studied. In an in vivo rat model of unilateral renal IR, animals were treated with Dexa, and serum renal function parameters, tissue injury and SGK-1 expression and localization were examined after different reperfusion times (2 h, 4 h and 24 h). Dexa at a dose of 2 mg/L exerted a protective effect on cell survival assessed by LDH release and vital staining paralleled by marked up-regulation of SGK-1. In rats, 2 mg/kg Dexa treatment 24 h prior to ischemia resulted in less severe tissue injury and ameliorated urea nitrogen levels 24 h after reperfusion. Furthermore, SGK-1 expression and phosphorylation were higher in Dexa animals demonstrated by Western blot and immunofluorescence technique. Our results provide novel data on the signalling mechanism of Dexa under hypoxia / ischemia and further support that Dexa emerges as an attractive pharmacological agent for the prevention of ischemic injury.
Authors:Á. Staszny, Enikő Havas, R. Kovács, B. Urbányi, G. Paulovits, Dóra Bencsik, Á. Ferincz, T. Müller, A. Specziár, Katalin Bakos, and Zs. Csenki
Intraspecific morphological variability may reflect either genetic divergence among groups of individuals or response of individuals to environmental circumstances within the frame of phenotypic plasticity. Several studies were able to discriminate wild fish populations based on their scale shape. Here we examine whether the variations in the scale shape in fish populations could be related to genetic or environmental factors, or to both of them. In the first experiment, two inbred lines of zebrafish, Danio rerio (Hamilton 1822) reared under identical environmental conditions were compared. Secondly, to find out what effect environmental factors might have, offsprings were divided into two groups and reared on different diets for 12 weeks. Potential recovery of scales from an environmental effect was also assessed. Experimental groups could successfully be distinguished according to the shape of scales in both experiments, and the results showed that both genetic and environmental factors may notably influence scale shape. It was concluded that scale shape analysis might be used as an explanatory tool to detect potential variability of environmental influences impacting genetically homogeneous groups of fish. However, due to its sensitivity to environmental heterogeneity, the applicability of this technique in identifying intraspecific stock membership of fish could be limited.