Highly pathogenic avian influenza virus subtype H5N1 in Mute swans in the Czech Republic     

Nagy A  Machova J  Hornickova J  Tomci M  Nagl I  Horyna B  Holko I 《Veterinary microbiology》2007,120(1-2):9-16

In order to determine the actual prevalence of avian influenza viruses (AIV) in wild birds in the Czech Republic extensive surveillance was carried out between January and April 2006. A total of 2101 samples representing 61 bird species were examined for the presence of influenza A by using PCR, sequencing and cultivation on chicken embryos. AIV subtype H5N1 was detected in 12 Mute swans (Cygnus olor). The viruses were determined as HPAI (highly pathogenic avian influenza) and the hemagglutinin sequence was closely similar to A/mallard/Italy/835/06 and A/turkey/Turkey/1194/05. Following the first H5N1 case, about 300 wild birds representing 33 species were collected from the outbreak region and tested for the presence of AIV without any positive result. This is the first report of highly pathogenic avian influenza subtype H5N1 in the Czech Republic. The potential role of swan as an effective vector of avian influenza virus is also discussed.  相似文献   

A density management diagram for Norway spruce in the temperate European montane region     

Giorgio Vacchiano  R. Justin Derose  John D. Shaw  Miroslav Svoboda  Renzo Motta 《European Journal of Forest Research》2013,132(3):535-549

Norway spruce is one of the most important conifer tree species in Europe, paramount for timber provision, habitat, recreation, and protection of mountain roads and settlements from natural hazards. Although natural Norway spruce forests exhibit diverse structures, even-aged stands can arise after disturbance or as the result of common silvicultural practice, including off-site afforestation. Many even-aged Norway spruce forests face issues such as senescence, insufficient regeneration, mechanical stability, sensitivity to biotic disturbances, and restoration. We propose the use of Density Management Diagrams (DMD), stand-scale graphical models designed to project growth and yield of even-aged forests, as a heuristic tool for assessing the structure and development of even-aged Norway spruce stands. DMDs are predicated on basic tree allometry and the assumption that self-thinning occurs predictably in forest stands. We designed a DMD for Norway spruce in temperate Europe based on wide-ranging forest inventory data. Quantitative relationships between tree- and stand-level variables that describe resistance to selected natural disturbances were superimposed on the DMD. These susceptibility zones were used to demonstrate assessment and possible management actions related to, for example, windfirmness and effectiveness of the protective function against rockfall or avalanches. The Norway spruce DMD provides forest managers and silviculturists a simple, easy-to-use, tool for evaluating stand dynamics and scheduling needed density management actions.  相似文献   

Effects of Endo- and Ectomycorrhizal Fungi on Physiological Parameters and Heavy Metals Accumulation of Two Species from the Family Salicaceae     

Libor Mrnka  Michal Kuchár  Zuzana Cieslarová  Pavel Matějka  Jiřina Száková  Pavel Tlustoš  Miroslav Vosátka 《Water, air, and soil pollution》2012,223(1):399-410

There is increasing interest in poplars and willows due to their biomass production and phytoremediation potential. They host two major types of mycorrhizal fungi that can substantially modulate the physiology of their hosts. In this study, the effects of endo- and ectomycorrhizal fungi on growth, physiological parameters, and heavy metals accumulation were studied in a pot experiment using Salix alba L. and Populus nigra L. The mycorrhizal fungi were inoculated separately and in combination to a soil substrate polluted by a mixture of heavy metals (mainly Cd, Pb, and Zn). Tree species differed in their mycorrhizal affinities, with poplar being colonized predominantly by Glomus intraradices and willow by Hebeloma mesophaeum. H. mesophaeum increased willow height and biomass, while G. intraradices decreased poplar height. The photosynthetic rate remained unchanged, and only minor changes were observed in the relative composition of photosynthetic pigments. Poplar photosynthetic rates and levels of photosynthetic pigments declined, while the epicuticular waxes in leaves increased toward the end of the experiment, irrespective of the inoculation. H. mesophaeum strongly reduced the accumulation of Cd and Fe in willow and poplar shoots, respectively. Our results support the use of selected mycorrhizal strains to tune phytoremediation outcomes in their plant hosts.  相似文献   

In Vitro Digestibility of Different Commercial Edible Algae Products     

Ludmila Machů  Dušan Samek  Jan Hrabě  Miroslav Fišera 《Journal Of Aquatic Food Product Technology》2013,22(5):423-435

Digestibility is an important factor in determining the level of nutritive factors utilization. Determination of in vitro digestibility in a Daisy incubator and assessment of protein digestibility using Kjeldahl method of algal food products after pepsin, pancreatin, and combined hydrolysis of both enzymes was described. The influence of different hydrolysis times on algal digestibility was investigated in brown seaweeds, red seaweeds, and green alga. The highest digestibility values were generally determined in red seaweeds after 24 h of combined hydrolysis by pepsin and pancreatin. Direct dependence between digestion time and digestion efficiency was verified and statistically proven.  相似文献   

Effect of (+)-limonene and 1-methoxy-2-propanol on Ips typographus response to pheromone blends     

Miroslav Blaženec  Rastislav Jakuš 《林业研究》2009,20(1):37-44

We compared two different strategies to increase the catches of Ips typographus (L.), particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone blends, targeting males and females respectively, in closely-spaced traps forming a barrier around forest stands. The second strategy, the single trap approach, used widely-spaced traps that were all baited with the same lure and intended to trap the highest possible numbers of males without compromising trapping of females. In the blend used for the barrier traps targeting primarily males, with a lower percentage of (4S)-cis-verbenol (cV), the (−)-α-pinene was replaced step wise with (+)-limonene at rates of 0%, 1%, 10%, 35%, 60% and 90%. This replacement had no significant effect on the numbers of responding I. typographus males, but there was a slight effect on the percentage of males caught. In the attractant blend for the barrier traps targeting females, with a higher percentage of cV, the 2-methyl-3-buten-2-ol (MB) was replaced with 1-methoxy-2-propanol (MP) in a similar fashion as for the male-specific blends. The replacement did not significantly affect the catch of females. Thus, it is possible to use the MP in the blend with cV and ipsdienol without significant change in catch efficacy. In the blends for single traps, the (−)-α- pinene was replaced with (+)-limonene and MB with MP. The replacement of (−)-α-pinene had only a slight effect on the percentage of males, but the results suggest that replacing MB with MP in the blend will not significantly reduce trapping efficacy. Foundation project: The research was supported by Slovak Research and Development Agency (APVV-51-P06005 and APVV-27-P05205) and by the Scientific Grant Agency of the Ministry of Education of the Slovak Republic and the Slovak Academy of Sciences (2/6153/26)  相似文献   

Structure of a Central-European mountain spruce old-growth forest with respect to historical development     

Miroslav Svoboda  Václav Pouska 《Forest Ecology and Management》2008

This study examines the structural characteristics of the tree layer, dead wood, canopy openings, and regeneration patterns of a spruce old-growth forest in the Bohemian Forest, Czech Republic. An old-growth stand with minor human influence and a stand that was presumably logged about 200 years ago were analyzed and compared, as some forest managers considered the presumable human impact as a reason for salvage logging. Even though the stands differed in tree density, height and DBH structure, it was not possible to conclude whether it was due to management history or the environmental differences. The volume of dead wood also differed between the stands. There was about 142 and 83 m³ ha⁻¹ of dead wood in the old-growth stand and presumably logged stand, respectively. The amount of dead wood found in the old-growth stand was comparable with values reported from spruce old-growth stands across Central Europe. In both stands, many canopy trees were arranged in linear patterns, which was a result of spruce regeneration on nurse logs. This suggests that the origin and development of the stands were characterized by natural processes and during the past 200 years typical old-growth structural characteristics have already evolved.  相似文献   

Molecular characterization of <Emphasis Type="Italic">Prune dwarf virus</Emphasis> cherry isolates from Slovakia shows their substantial variability and reveals recombination events in PDV RNA3     

Lukáš Predajňa  Nina Sihelská  Daniela Benediková  Katarína Šoltys  Thierry Candresse  Miroslav Glasa 《European journal of plant pathology / European Foundation for Plant Pathology》2017,147(4):877-885

Although Prune dwarf virus (PDV) is one of the most common viruses infecting stone fruits (Prunus spp.), most of the molecular diversity studies have so far focused on the capsid protein (CP) gene. An alternative diagnostic primer pair targeting the movement protein (MP) gene was used in the present work, increasing then polyvalence of PDV detection in cherry samples from Slovakia as compared to the previously published primers amplifying 5′MP-intergenic region-CP-3′UTR fragment. The nearly complete sequence of the RNA3 from 24 Slovak PDV isolates was determined, together with 19 partial sequences of the MP gene for other isolates. Even though the isolates originated from a geographically limited region, analyses showed a high degree of nucleotide sequence diversity between isolates. No clear-cut phylogenetic grouping based on host or geographical origin could be observed. The topology of the MP and CP trees were incongruent for some isolates. Highly supported recombination signals were detected in five PDV isolates, with breakpoints located at different positions in the central part of RNA3, within or close to the intergenic region. Taken together these results extend our understanding of the variability of PDV and for the first time highlight the contribution of recombination to the evolutionary history of this virus.  相似文献   

The influence of soil organic matter fractions on aggregates stabilization in agricultural and forest soils of selected Slovak and Czech hilly lands     

Nora Polláková  Vladimír Šimanský  Miroslav Kravka 《Journal of Soils and Sediments》2018,18(8):2790-2800

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Changes of sperm morphology,volume, density,and motility parameters in northern pike during the spawning period     

Volodymyr Bondarenko  Miroslav Blecha  Tomas Policar 《Fish physiology and biochemistry》2018,44(6):1591-1597

Sexually mature males (BW?=?1600?±?150 g and TL?=?235?±?30 mm) of northern pike (Esox lucius L.) were randomly selected from a pond to record changes in their sperm quality parameters (spermatozoa morphology, sperm volume, density, and motility parameters) during the spawning season. The morphological and motility parameters changed significantly during the reproductive season with following trends. Only, head width was not changed during the spawning season. The longest spermatozoa and its flagellar length were found at the middle of spawning period (TL?=?38.24?±?0.37 μm and 35.14?±?0.26 μm) and shortest at the beginning of spawning period (TL?=?34.81?±?0.29 μm and 32.53?±?0.18 μm). Other morphological characters were always the lowest at the beginning of spawning period. Sperm volume was changed from 0.33?±?0.3 ml in February, 0.43?±?0.2 ml in March to 0.24?±?0.1 ml in April, and density from 16.2?±?0.2?×?109 spermatozoa ml^?1 in February, 19.4?±?0.2?×?109 spermatozoa ml^?1 in March to 4.8?±?0.2?×?109 spermatozoa ml^?1 in April. Same sperm velocity was observed in all spawning terms at 10 and 20 s after activation. Higher velocity was found at 30 and 40 s after activation in sperm collected at the middle and the end of spawning period. Significantly, higher percentage of motile sperm was observed at 20, 30, and 40 s after activation in sperm sampled at the end of spawning period. This study supports the hypothesis that longer spermatozoa swim faster.  相似文献   

Genetic investigation and cytological comparison of two genic male sterile lines 9012A and MSL in <Emphasis Type="Italic">Brassica napus</Emphasis> L.     

Cancan Luo  Yanyan Sun  Yunxiao Zhang  Yuan Guo  Miroslav Klima  Shengwu Hu 《Euphytica》2018,214(7):124

Genic male sterility (GMS) is one of the effective pollination control systems in hybrid rapeseed (Brassica napus L.) breeding. The recessive GMS lines 9012A and Lembke (MSL) have made a great contribution to the utilization of heterosis in rapeseed. Cytological observation and genetic investigation were employed to reveal anther abortion characters and genetic relationship of 9012A and MSL. Cytological and transmission electron microscopy observation revealed that anther abortion of 9012A and MSL initiated at the microsporocyte stage, both lines showed premature or retarded degradation of tapetum. Some anthers in 9012A developed to the microspore stage since their tapetal cells changed to the secretory type. However, MSL anthers did not progress to the tetrad stage, since the tapetum did not change to the secretory type. Genetic investigation revealed that MSL and 9012A had the same temporary maintainer system, while their cytoplasm types were different. The cytoplasm of MSL was similar to Cam while 9012A was similar to Nap type. The results laid a solid foundation for utilization of the two male sterile lines in rapeseed hybrid breeding.  相似文献