Polymethoxy-1-alkenes from Aphanizomenon ovalisporum Inhibit Vertebrate Development in the Zebrafish (Danio rerio) Embryo Model     

Asha Jaja-Chimedza  Miroslav Gantar  Patrick D. L. Gibbs  Michael C. Schmale  John P. Berry 《Marine drugs》2012,10(10):2322-2336

Cyanobacteria are recognized producers of a wide array of toxic or otherwise bioactive secondary metabolites. The present study utilized the zebrafish (Danio rerio) embryo as an aquatic animal model of vertebrate development to identify, purify and characterize lipophilic inhibitors of development (i.e., developmental toxins) from an isolate of the freshwater cyanobacterial species, Aphanizomenon ovalisporum.Bioassay-guided fractionation led to the purification, and subsequent chemical characterization, of an apparent homologous series of isotactic polymethoxy-1-alkenes (1–6), including three congeners (4–6) previously identified from the strain, and two variants previously identified from other species (2 and 3), as well as one apparently novel member of the series (1). Five of the PMAs in the series (1–5) were purified in sufficient quantity for comparative toxicological characterization, and toxicity in the zebrafish embryo model was found to generally correlate with relative chain length and/or methoxylation. Moreover, exposure of embryos to a combination of variants indicates an apparent synergistic interaction between the congeners. Although PMAs have been identified previously in cyanobacteria, this is the first report of their apparent toxicity. These results, along with the previously reported presence of the PMAs from several cyanobacterial species, suggest a possibly widespread distribution of the PMAs as toxic secondary metabolites and warrants further chemical and toxicological investigation.  相似文献   

Determination of areas with the most significant shift in persistence of pests in Europe under climate change     

Eva Svobodová  Miroslav Trnka  Martin Dubrovský  Daniela Semerádová  Josef Eitzinger  Petr Štěpánek  Zdeněk Žalud 《Pest management science》2014,70(5):708-715

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Trends in import and export of fishery products in the Czech Republic during 2010–2015     

Václav Nebeský  Tomáš Policar  Miroslav Blecha  Jiří Křišťan  Petr Svačina 《Aquaculture International》2016,24(6):1657-1668

There has been a worldwide increase in consumption of fish from open waters and aquaculture during the last decades. In 2013, the Czech Republic was the sixth largest producer of fish within the EU, with annual production of 20,135 tonnes. However, during the period 2010–2015 import of fishery products to the Czech Republic increased from 39,098 to 43,399 tonnes. The monetary value of import increased by 81 % from 90.2 million EUR in 2010 to 169.9 million EUR in 2015. In 2010, the major imported fishery product was frozen fillets of sutchi catfish (Pangasianodon hypophthalmus) from Vietnam (8872 tonnes). In 2015, the most imported fishery product was whole chilled salmon (Salmo salar) from Norway (6897 tonnes). During 2010–2015, the export of fishery products increased from 18,167 to 22,134 tonnes, which is an increase by 21.8 %. The value of export has increased by 80 % from 54.5 million EUR in 2010 to 98.1 million EUR in 2015. The major exported fish was live common carp (Cyprinus carpio) at volume of 7545–9075 tonnes. This study looks at changes in market, volume and value of fish imported and exported during the last 6 years.  相似文献   

(+)-柠檬烯和1-甲氧基-2-丙醇对云杉八齿小蠹虫对信息素混合物反映的影响(英文)     

Miroslav Blazenec  Rastislav Jaku 《林业研究》2009,20(1)

对利用信息素诱捕云杉八齿小蠹的策略进行了对比分析,尤其是雄性小蠹的诱捕。第一种策略是障碍法,在林分的周围密集的布置捕捉陷阱,使用交互式信息素分别诱捕雄性小蠹和雌性小蠹。第二种策略是单一诱捕法,广阔使用投有相同诱饵诱捕陷阱,以捕捉最大数量的雄性小蠹为目的,而不包含雌性小蠹的捕捉。在带有低含量的(4S)一反式马鞭草烯醇诱饵混合物中,用0%,1%,10%,35%,60%and90%的(+)-柠檬烯逐步取代α-蒎烯。这种替换对雄性小蠹的反映数量没有影响,但对雄性小蠹的捕捉量稍有影响。在有高含量(4S)-反式马鞭草烯醇捕捉雌性小蠹的引诱剂混合物中,用1-甲氧基-2-丙醇取代2-甲基-3-丁烯-2-醇,对雌性小蠹的捕捉率没有影响。因而,在具有反式马鞭草烯醇和(4县)-2-甲基-6-甲基-2,7-辛-4-醇的混合物中使用1-甲氧基-2-丙醇,捕捉效果没有明显的变化。在单一捕捉的引诱剂混合物中,用(+)-柠檬烯取代α-蒎烯,用1-甲氧基-2-丙醇取代2-甲基-3-丁烯-2-醇,α-蒎烯被代替后对雄性小蠹的捕捉率轻微的影响,但2-甲基-3-丁烯-2-醇被代替后,将不会没有明显地降低捕捉效果。  相似文献   

Dynamics of windthrow events in a natural fir-beech forest in the Carpathian mountains     

Pavel Šamonil  Lukáš Antolík  Miroslav Svoboda  Dušan Adam 《Forest Ecology and Management》2009

The age of single windthrows (single uprooted trees and/or pit/mound microtopographical pairs) in a natural fir-beech forest was assessed in the flysch zone of the Outer Western Carpathians. The following characteristics were evaluated for all 1562 single windthrows occurring in a 10.8 ha area: dimensions; thickness of organic and upper mineral soil horizons both on mounds and in pits; and the presence of new trees taking root on the windthrows. For more recent windthrows, selected quantitative and qualitative characteristics of the uprooted trees were evaluated. A suppositional gradient of age (SGA) was constructed based on the windthrow characteristics using principal component analysis. A representative sample of windthrows was dated along the SGA with the use of dendroecological techniques and historic records from 1972 and 1995. For European beech (Fagus sylvatica L.) we were able to measure the actual threshold of release value – at 12% of growth change. The age of windthrows was determined in 37 of a total of 51 cases. The development of windthrow properties over time was studied. Age explained 33.7% of the variability in the measured windthrow characteristics (F = 19.31, p = 0.0002, measured characteristics see above). A multiple regression model (R² = 0.844, F = 65.62, p < 1 × 10⁻⁶) was constructed to evaluate the age of undated windthrows. The best predictors of age were: ordinal classification of trunk disintegration and thickness of F and A horizons on the mound.  相似文献   

Fish to 2030: The Role and Opportunity for Aquaculture     

Mimako Kobayashi  Siwa Msangi  Miroslav Batka  Stefania Vannuccini  Madan M. Dey  James L. Anderson 《Aquaculture Economics & Management (Blackwell Science)》2015,19(3):282-300

Seafood sector can contribute to the global food supply in an important way, and provide an important source of animal protein. Based on observed regional trends in seafood production and consumption and using a global, partial-equilibrium, multi-market model, this study investigates what the global seafood market may look like in 2030. The model projects that the total fish supply will increase from 154 million tons in 2011 to 186 million tons in 2030, with aquaculture entirely responsible for the increase. The fastest aquaculture growth is expected for tilapia and shrimp, while the largest expansion is expected in India, Latin America and Caribbean and Southeast Asia. Fast-growing seafood demand in China and elsewhere represents a critical opportunity for global fisheries and aquaculture to improve their management and achieve sustainable seafood economy.  相似文献   

Fertilizing ability of gametes at different post‐activation times and the sperm–oocyte ratio in the artificial reproduction of pikeperch Sander lucioperca          下载免费PDF全文

Jiri Kristan  Daniel Zarski  Miroslav Blecha  Tomas Policar  Oleksandr Malinovskyi  Azin Mohagheghi Samarin  Katarzyna Palinska‐Zarska  Joanna Nowosad  Slawomir Krejszeff  Dariusz Kucharczyk 《Aquaculture Research》2018,49(4):1383-1388

The time period during which oocyte and spermatozoa retain their fertilizing ability after contacting with water was evaluated in pikeperch (Sander lucioperca). In addition, success of in vitro fertilization was examined regarding to the sperm‐to‐oocyte ratio (SOR). In the first trial, oocytes were placed in Petri dishes containing 5 ml of the hatchery water, to which freshly collected and pooled sperm were added to each sample at 0, 15, 30, 60, 90, 120, 150 and 180 s post oocyte activation. The oocytes retained their fertility for at least 30 s after contacting with water. The second trial tested the maximum time period during which spermatozoa retained fertilizability after contacting with water. Milt (50 μl) was collected from each male and added to 5 ml of water in Petri dishes. Thereafter, oocytes were added at 0, 5, 15, 30, 60 and 75 s post‐sperm activation. Delays exceeding 10 s affected negatively the fertilization success. The third trial examined the optimum SOR; in which was found that 100 × 10³ spermatozoa per oocyte were the minimum ratio to ensure fertilization rates above 70%. Overall, the data clarified some biological interactions of gametes in the artificial propagation of pikeperch.  相似文献   

Millipedes (Diplopoda) in birds nests     

Karel Tajovský  Andrej Mock  Miroslav Krumpl 《European Journal of Soil Biology》2001,37(4)

Nests of birds represent an unusual microhabitat for diverse groups of soil and epigeic invertebrates including millipedes. The millipede faunas of 301 birds nests from 63 localities throughout Slovakia were obtained by heat extraction of the nest substrates. In total 18 species of millipedes were found in 7 different types of nests of 40 bird species. The most frequent millipede species were Polyxenus lagurus and Proteroiulus fuscus. The similarities in the millipede nidifauna depending on the type of nests, ecological characteristics and geographical distribution of millipede species are discussed.  相似文献   

Comparison of responses to drought stress of 100 wheat accessions and landraces to identify opportunities for improving wheat drought resistance*     

Dejan Dodig  Miroslav Zorić  Vesna Kandić  Dragan Perović  Gordana Šurlan‐Momirović 《Plant Breeding》2012,131(3):369-379

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Role of extracellular polysaccharide in the colonization of wheat (Triticum vulgare L.) roots by N2-fixing cyanobacteria     

Miroslav Gantar  Peter Rowell  Nigel W. Kerby  Ian W. Sutherland 《Biology and Fertility of Soils》1995,20(1):41-48

The characteristics of the mucilaginous sheaths of the cyanobacteria Nostoc 2S9B and Anabaena C5 and their role in the formation of associations with the roots of wheat plants grown in liquid culture have been assessed. Light and scanning electron microscopy revealed that the filaments of Nostoc 2S9B that formed a tight association with the root surface were contained in a firm mucilaginous shell. In contrast, filaments of Anabaena C5 formed a loose association and were easily detached from the mucilage that had a sheet-like appearance and tended to disintegrate as the culture aged. Similarly, there was a tight attachment of the isolated polysaccharide from Nostoc 2S9B to the root surface and a loose attachment of the Anabaena C5 polysaccharide. When the crude polysaccharide from Nostoc 2S9B was freed from proteins by phenol or pronase treatment, its ability to adhere to the root surface was lost or considerably reduced, suggesting that a protein component contributes to the tight attachment of Nostoc 2S9B. The crude polysaccharide preparation from Nostoc 2S9B contained 2.8% (w/w) protein while that from Anabaena C5 was only 0.6% (w/w) protein. The purified exopolysaccharide from Nostoc 2S9B contained three neutral sugars and glucuronic acid, whereas fucose and a uronic acid were the main components of that from Anabaena C5. Washing the roots or treating them with different sugars did not alter the ability of Nostoc 2S9B to colonize the root surface, indicating that cyanobacterial attachment may not be specific.  相似文献