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排序方式: 共有216条查询结果,搜索用时 156 毫秒
211.
Hamilton SR Davidson RC Sethuraman N Nett JH Jiang Y Rios S Bobrowicz P Stadheim TA Li H Choi BK Hopkins D Wischnewski H Roser J Mitchell T Strawbridge RR Hoopes J Wildt S Gerngross TU 《Science (New York, N.Y.)》2006,313(5792):1441-1443
Yeast is a widely used recombinant protein expression system. We expanded its utility by engineering the yeast Pichia pastoris to secrete human glycoproteins with fully complex terminally sialylated N-glycans. After the knockout of four genes to eliminate yeast-specific glycosylation, we introduced 14 heterologous genes, allowing us to replicate the sequential steps of human glycosylation. The reported cell lines produce complex glycoproteins with greater than 90% terminal sialylation. Finally, to demonstrate the utility of these yeast strains, functional recombinant erythropoietin was produced. 相似文献
212.
Piotr Tryjanowski Tim H. Sparks Andrzej Blecharczyk Irena Małecka-Jankowiak Stanisław Switek Zuzanna Sawinska 《American Journal of Potato Research》2018,95(1):26-32
Potato Solanum tuberosum is one of the world’s four most important crops. Its cultivation is steadily increasing in response to the need to feed a growing world population. The yield of potato is influenced inter alia by both climate and pests. The main defoliator pest of potato is Colorado potato beetle Leptinotarsa decemlineata. Using data from a long-term experiment (1958–2013) in western Poland, we show that increasing temperature has affected the trophic relationship between potato and Colorado potato beetle. The planting, leafing, flowering and harvest dates for potato were advanced, after controlling for different cultivars, by 2.00 days, 3.04 days, 3.80 days and 3.42 days respectively for every 1 °C increase in temperature. In contrast, first treatment against Colorado potato beetle advanced by 4.66 days for every 1 °C increase in temperature, and, furthermore, the number of treatments against the beetle increased by 0.204 per 1 °C increase in temperature. This suggests that the beetle responds faster to increasing temperature than the plant does, but both parts of the system are probably greatly modified by farming practices. 相似文献
213.
Predation impact of common backswimmer (Notonecta glauca L.) on juvenile narrow‐clawed crayfish (Astacus leptodactylus Esch.)
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The aim of the study was to investigate the effect of the presence of common backswimmer Notonecta glauca and their potential predation, on growth, mortality, survival and cheliped loss of juvenile narrow‐clawed crayfish Astacus leptodactylus. The presence of N. glauca in tanks during the day caused a radical change in the behaviour of juvenile A. leptodactylus, which remained for more time in hiding places. At night, such differences in crayfish behaviour were not found. The negative effect of N. glauca in tanks on crayfish total body length and body weight was statistically significant (p < .05). The crayfish survival decreased with increasing the number N. glauca in tanks. The crayfish mortality in the first week was higher than in the second week. The effect of the presence of N. glauca in tanks on crayfish chelae autotomy was statistically significant (p < .05). The number of crayfish with complete sets of chelipeds decreased and the number of crayfish with loss of chelipeds increased when the number of N. glauca in tanks increased. Common backswimmers N. glauca have been effective predators not only of victims caught on the surface of water, but also of bottom‐dwelling organisms such as juvenile crayfish. 相似文献
214.
Izabela Polowczyk Piotr Cyganowski Justyna Ulatowska Wojciech Sawiński Anna Bastrzyk 《Water, air, and soil pollution》2018,229(6):203
Removal of arsenic from water reservoirs is the issue of great concern in many places around the globe. As adsorption is one of the most efficient techniques for treatment of As-containing media, thus the present study concerns application of iron oxides-hydroxides (akaganeite) as adsorbents for removal of this harmful metal from aqueous solution. Two types of akaganeite were tested: synthetic one (A) and the same modified using hexadecyltrimethylammonium bromide (AM). Removal of As was tested in batch studies in function of pH, adsorbent dosage, contact time, and initial arsenic concentration. The adsorption isotherms obey Langmuir mathematical model. Adsorption kinetics complies with pseudo-second-order kinetic model, and the constant rates were defined as 2.07?×?10?3and 0.92?×?10?3 g mg?1 min?1 for the samples (A) and (AM), respectively. The difference was caused by significant decrease in adsorption rate in initial state of the process carried out for the sample AM. The maximum adsorption capacity achieved for (A) and (AM) akaganeite taken from Langmuir isotherm was 148.7 and 170.9 mg g?1, respectively. The results suggest that iron oxides-hydroxides can be used for As removal from aqueous solutions. 相似文献
215.
The objective of this study was to assess soil tillage methods by years interaction for dry matter of plant yield of maize(Zea mays L.) grown in West Poland by the additive main effects and multiplicative interaction model. The study comprised four soil tillage methods, analysed in 12 years through field trials arranged in a randomized complete block design, with four replicates. Dry matter of plant yield of the tested soil tillage methods varied from 86.7 dt ha~(–1)(for no-plough tillage in 2005) to 246.4 dt ha~(–1)(for complete conventional tillage in 2012), with an average of 146.6 dt ha~(–1). In the variance analysis, 49.07% of the total dry matter of plant yield variation was explained by years, 12.69% by differences between soil tillage methods, and 10.53% by soil tillage methods by years interaction. Dry matter of plant yield is highly influenced by soil tillage methods by years factors. 相似文献
216.
Robert Jankowiak Beata Strzałka Piotr Bilański Magdalena Kacprzyk Karolina Lukášová Riikka Linnakoski Sebastian Matwiejczuk Marcin Misztela Robert Rossa 《European Journal of Forest Research》2017,136(5-6):939-956
Bark beetles (Coleoptera: Curculionidae, Scolytinae) are commonly recognised as important agents of tree mortality in coniferous forests of the Western Carpathians. They, together with weevils, are consistently associated with ophiostomatoid fungi. Information regarding conifer beetle-associated fungi in the Western Carpathians remains incomplete and unreliable, particularly with respect to fir-infesting bark beetles. This study aims to clarify associations between fungi in the genera Graphilbum, Leptographium, Ophiostoma and Sporothrix (Ophiostomatales) and their beetle vectors in Norway spruce (Picea abies), European larch (Larix decidua) and silver fir (Abies alba). Samples associated with 20 bark beetle species and weevils were collected from nine stands in Poland and the Czech Republic. Fungi were isolated from adult beetles and galleries. Isolates were identified based on morphology, DNA sequence comparisons for four gene regions (ITS, LSU, ß-tubulin, TEF 1-α) and phylogenetic analyses. In total, 46 distinct taxa were identified, including 25 known and 21 currently unknown species. Several associations between fungi and subcortical insects were recorded for the first time. In addition, O. borealis and O. quercus were detected from A. alba for the first time. The composition of the fungal communities varied among the studied tree species and to a lesser degree among the beetle species. The spruce-infesting bark beetles were commonly associated with species of Leptographium s. l. and Ophiostoma s. str.; the larch-infesting bark beetles were often associated with Ophiostoma s. str. and Sporothrix, while the fir-infesting bark beetles were commonly associated with Ophiostoma s. str. and Graphilbum. The most commonly encountered fungal associates of the examined insects were (a) Grosmannia cucullata, G. piceiperda, Grosmannia sp. 1, Ophiostoma macroclavatum and O. piceae with the spruce-infesting bark beetles; (b) O. pseudocatenulatum and Sporothrix sp. 1 with the larch-infesting bark beetles; and (c) O. piceae, Ophiostoma sp. 2 and Graphilbum sp. 2 with the fir-infesting bark beetles. The differences in fungal associates among the bark beetle species occurring on P. abies, L. decidua and A. alba could be linked to the different habitats that these beetles occupy. 相似文献