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241.
Migration counts can offer a cost-effective method for monitoring the state of migrant raptor populations. However, differential migration strategies between inexperienced juveniles and experienced non-juveniles are rarely accounted for when inferring population trends from raptor migration counts. Since 2011, the Batumi Raptor Count (BRC) monitors the autumn migration of more than 1 million raptors along the eastern Black Sea coast in the Republic of Georgia. We also systematically sampled age information to assess differential migration timing between age groups and estimate age-specific linear trends in abundance between 2011 and 2018 for eight focal species. In so doing we aimed (1) to reassess the global relevance of BRC counts for each species and the potential for monitoring abundance of juveniles and non-juveniles, and (2) to identify demographic changes underlying recent trends in overall abundance. We found that the mean annual passage of non-juveniles at Batumi represents at least 1% of the estimated global breeding population of five study species. As expected, counts of juveniles were more variable than counts of non-juveniles. Yet despite our short monitoring period our models had sufficient statistical power to detect changes in abundance of 10%/year or less for at least one age group in all species except Pallid Harrier Circus macrourus. Our results indicate stable abundance and demography for half of the study species. We also found strong and significant increases in the abundance of Black Kites Milvis migrans and Short-toed Eagles Circaetus gallicus that were primarily due to increasing numbers of non-juveniles. By contrast, juvenile Montagu's Harriers Circus pygargus and Booted Eagles Hieraaetus pennatus significantly decreased in abundance. The first decade of BRC surveys offers an important benchmark for monitoring raptor populations using the eastern African–Palearctic flyway in the 21st century. We discuss possible causes of the observed trends and hope our work will stimulate demographic monitoring at migration count sites.  相似文献   
242.
Many pathways of primary metabolism are substantially conserved within and across plant families. However, significant differences in organization and fluxes through a reaction network may occur, even between plants in closely related genera. Assessing and understanding these differences is key to appreciating metabolic diversity, and to attempts to engineer plant metabolism for higher crop yields and desired product profiles. To better understand lipid metabolism and seed oil synthesis in canola (Brassica napus), we have characterized four canola homologues of the Arabidopsis (Arabidopsis thaliana) ROD1 gene. AtROD1 encodes phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), the enzyme that catalyzes a major flux of polyunsaturated fatty acids (PUFAs) in oil synthesis. Assays in yeast indicated that only two of the canola genes, BnROD1.A3 and BnROD1.C3, encode active isozymes of PDCT, and these genes are strongly expressed during the period of seed oil synthesis. Loss of expression of BnROD1.A3 and BnROD1.C3 in a double mutant, or by RNA interference, reduced the PUFA content of the oil to 26.6% compared with 32.5% in the wild type. These results indicate that ROD1 isozymes in canola are responsible for less than 20% of the PUFAs that accumulate in the seed oil compared with 40% in Arabidopsis. Our results demonstrate the care needed when translating results from a model species to crop plants.  相似文献   
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Extracellular proteins in plant embryogenesis.   总被引:14,自引:0,他引:14  
In many plant species nonzygotic embryos can develop from diploid somatic cells grown in tissue culture. Extracellular glycoproteins have been identified that can rescue arrested somatic embryos. One of these glycoproteins may be part of a mechanism that controls the expansion of plant cells.  相似文献   
246.
Inland Antarctic nunataks typically have simple physically weathered soils and limited ecosystem complexity. In this paper we present quantitative measurements of soil physical and chemical properties at one Antarctic nunatak. We measured pH, grain size, field capacity, soil organic carbon, phosphate, nitrate, ammonium and the cations magnesium, calcium and potassium along two transects. The data obtained indicated that very low levels of nutrients were present/available to biota, and that liquid water was absent, at least from the surface depths of soil, except during periods of active snow melt. Consequently, biological activity is severely limited. We conclude that, due to the climatic and microclimatic conditions at this location, the development of biological communities and soils is maintained in an extremely simple but still apparently stable ‘quasi climax’ state. Increased soil development and biological complexity can be expected if the contemporary rapid regional warming in the Antarctic Peninsula region continues.  相似文献   
247.
Pneumothorax is a mild complication during pacemaker lead implantation using the subclavian puncture technique. We report on five-year experience in 433 pacemaker lead implantation procedures in 379 patients. The cephalic vein route was solely used in twelve patients. Three procedures were performed over time in four patients and one patient needed four repetitive punctures for pacemaker lead implantation and replacement. Thus 421 punctures were carried out in 367 patients. Eleven case of pneumothorax were observed: in eight patients (1.9%) a partial pneumothorax occurred and in three patients (0.7%) the pneumothorax was nearly complete. In the latter patients a chest tube was inserted and hospital admission was prolonged for 3, 6 and 6 days, respectively. Old age with a corresponding abnormality in the form of chest deformation were predominantly found in the patients with this type of complication.  相似文献   
248.
Aspartylglucosaminuria (AGU) is a recessive autosomally inherited lysosomal storage disorder due to deficiency of the enzyme aspartylglucosaminidase (AGA). The structural gene for this human enzyme (AGA) has been assigned to the region 4q21----qter. We determined the AGA activity in cultured fibroblasts of a girl with a 46,XX,del(4)(q33) karyotype. The results indicate that the girl is a hemizygote for AGA, permitting the assignment of human AGA to the region 4q33----qter.  相似文献   
249.
Non-embryogenic carrot suspension cells secrete the EP1 glycoprotein. A cDNA clone encoding EP1 was isolated and sequenced. The EP1 sequence revealed a region of homology with Brassica S-locus glycoprotein genes, an Arabidopsis S-like gene and putative S-like receptor protein kinases from maize and Arabidopsis. EP1 gene expression, analysed by in situ mRNA localization, was detected in cells located at the surface of the seedling: in the epidermis of the root, the hypocotyl and the cotyledons, in the root cap, and in a crescent of cells in the apical dome of the shoot. In developing seeds, expression was most pronounced in both the inner and outer integument epidermis.  相似文献   
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