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51.
We studied habitat selection of three-toed woodpecker (TTW) in relation to forest structural variables, habitat types and hydrological conditions in north-eastern Poland. Based on known locations of 34 breeding pairs and the data on location of forest areas with high conservation value (referred to as Biologically Important Forests), we created a habitat prediction model for TTW using a Maxent algorithm. We found that this species most often selected breeding sites characterized by high contribution of old-growth stands with uneven vertical structure and considerable amount of very old trees of previous generations, as well as boreal spruce-dominated bogs and riverine forests. Such sites were preferred regardless of their actual protection status, which leads to the following conclusion: although existing forest reserves are very important to three-toed woodpecker, suitable habitats with similar characteristics can still be found outside protected areas and are also utilized by the species. However, such sites outside reserves are threatened by fragmentation due to timber extraction. Therefore it is recommended to protect these sites by either including them into existing reserves or putting them under special management schemes.  相似文献   
52.
Of the various alternatives for cloning elite conifers, somatic embryogenesis (SE) appears to be the best option. In recent years, significant areas of lodgepole pine (Pinus contorta) forest have been devastated by the mountain pine beetle (MPB) in Western Canada. In an attempt to establish an SE propagation system for MPB-resistant lodgepole pine, several families displaying varying levels of resistance were selected for experimentation involving shoot bud and immature seed explants. In bud cultures, eight embryogenic lines were induced from 2 of 15 genotypes following various treatments. Genotype had an important influence on embryogenic culture initiation, and this effect was consistent over time. These lines were identified by microscopic observation and genetic markers. Despite the abundance of early somatic embryos, the cultures have yet to develop into mature embryos. In contrast, immature zygotic embryos (ZEs) cultured from megagametophytes initiated SE at an early dominance stage via nodule-type callus in 1 of 10 genotypes. As part of the study, putative embryogenesis-specific genes, WOX2 (WUSCHELL homeobox 2) and HAP3A, were analyzed in cultures of both shoot bud explants and ZEs. On the basis of these analyses, we postulate that PcHAP3A was expressed mainly in callus and may be involved in cell division, whereas WOX2 was expressed mainly in embryonal mass (EM)-like tissues. The findings from this study, based on molecular assessment, suggest that the cell lines derived from bud cultures were truly EM. Moreover, these experimental observations suggest that PcWOX2 could be used as an early genetic marker to discriminate embryogenic cultures from callus.  相似文献   
53.
Characteristics of the Type III optical difference spectra of 13 methylenedioxyphenyl compounds in NADPH-fortified armyworm midgut microsomes varied with the nature of the substituents in the aromatic ring. Compounds with electron-donating substituents yielded spectra with large 427458nm peak ratios, whereas those with electron-withdrawing groups exhibited low 427458nm peak ratios. Small amounts of carbon monoxide were generated during incubation of the 4,5-dihalo derivatives with midgut microsomes, and cis- and trans-methylenedioxycyclohexanes exhibited spectra with a major Soret peak at about 430 nm and a very weak absorbance maximum at about 480 nm. Formation of the Type III spectral complex occurred very rapidly and was associated with a marked decrease (up to 72%) in cytochrome P-450 levels as measured by carbon monoxide binding. Although a 24% reduction of cytochrome P-450 was observed in the absence of any measureable 458-nm spectral complex a linear relationship existed between further decreases in the cytochrome and the increase in Type III complex formation (458 nm). Inhibitory potencies of the compounds towards aldrin epoxidase and benzopyrene hydroxylase activities were not clearly correlated with either spectral complex formation or decrease in cytochrome P-450 and it is apparent that different factors are involved in the inhibition of different monooxygenase reactions.  相似文献   
54.
Selenium (Se) is an important element from the environmental and biological point of view. In the world, deficiency of Se in a diet occurs more often and nutritional supplements are recommended.The ability of several plants to accumulate and transform inorganic Se forms into its bioactive organic compounds has important implications for human nutrition and health. This work gives a brief overview of the study carried out to characterize Se species produced by different enriched edible plants which were grown in the presence of different Se species.  相似文献   
55.
New Forests - Cultivation of seedlings in trays requires the use of specifically developed substrates. This study presents the results of the analyses of selected physical and mechanical parameters...  相似文献   
56.
57.
Antimicrobial peptides (AMPs) are found widespread in nature and possess antimicrobial and immunomodulatory activities. Due to their multifunctional properties, these peptides are a focus of growing body of interest and have been characterized in several fish species. Due to their similarities in amino-acid composition and amphipathic design, it has been suggested that neuropeptides may be directly involved in the innate immune response against pathogen intruders. In this review, we report the molecular characterization of the fish-specific AMP piscidin1, the production of an antibody raised against this peptide and the immunohistochemical identification of this peptide and enkephalins in the neuroepithelial cells (NECs) in the gill of several teleost fish species living in different habitats. In spite of the abundant literature on Piscidin1, the biological role of this peptide in fish visceral organs remains poorly explored, as well as the role of the neuropeptides in neuroimmune interaction in fish. The NECs, by their role as sensors of hypoxia changes in the external environments, in combination with their endocrine nature and secretion of immunomodulatory substances would influence various types of immune cells that contain piscidin, such as mast cells and eosinophils, both showing interaction with the nervous system. The discovery of piscidins in the gill and skin, their diversity and their role in the regulation of immune response will lead to better selection of these immunomodulatory molecules as drug targets to retain antimicrobial barrier function and for aquaculture therapy in the future.  相似文献   
58.
The aim of this study was to determine the impact of feeding juvenile pikeperch diets with medicinal herb adjuvants on the growth performance, proximate body composition, fatty acids profile (whole fish, muscle tissues, viscera) and cytological and histological indicators of the liver and middle intestine. The fish (mean body weight of ca. 110 g) were fed diets with a 0.1% supplement of Astragalus radix (group A), Lonicera japonica (group L) or a mixture of these herbs ( A. radix + L. japonica ; group A/L) for 8 weeks. The herbal supplementation was not noted to have had an impact on the analysed indicators of fish growth performance, condition or feed conversion ratio ( P >0.05). Statistically significant intergroup differences were noted in the value of the hepatosomatic index, hepatocyte size, their nucleus and nucleus/cytoplasm diameter ratio ( P <0.05). Significant intergroup differences were also noted in the appearance of the hepatic parenchyma. Statistically significant intergroup differences were also noted in the protein content of the whole fish body. The analysis of the proximal composition of the fish viscera, in turn, indicated significant differences in the fat content ( P <0.05). Among the analysed group of fatty acids (saturated – SFA, monoenoic – MUFA, polyenoic – PUFA) contained in the whole fish, the fillets and the viscera, significant intergroup differences were noted with regard to SFA (viscera) and MUFA (whole fish) ( P <0.05). The total PUFA content was stable, although significant intergroup differences were noted with regard to a few of the acids that belong to this group ( P <0.05).  相似文献   
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