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1.
Joran Martijn Anders E. Lind Max E. Schön Ian Spiertz Lina Juzokaite Ignas Bunikis Olga V. Pettersson Thijs J. G. Ettema 《Environmental microbiology》2019,21(7):2485-2498
Amplicon sequencing of the 16S rRNA gene is the predominant method to quantify microbial compositions and to discover novel lineages. However, traditional short amplicons often do not contain enough information to confidently resolve their phylogeny. Here we present a cost-effective protocol that amplifies a large part of the rRNA operon and sequences the amplicons with PacBio technology. We tested our method on a mock community and developed a read-curation pipeline that reduces the overall read error rate to 0.18%. Applying our method on four environmental samples, we captured near full-length rRNA operon amplicons from a large diversity of prokaryotes. The method operated at moderately high-throughput (22286–37,850 raw ccs reads) and generated a large amount of putative novel archaeal 23S rRNA gene sequences compared to the archaeal SILVA database. These long amplicons allowed for higher resolution during taxonomic classification by means of long (∼1000 bp) 16S rRNA gene fragments and for substantially more confident phylogenies by means of combined near full-length 16S and 23S rRNA gene sequences, compared to shorter traditional amplicons (250 bp of the 16S rRNA gene). We recommend our method to those who wish to cost-effectively and confidently estimate the phylogenetic diversity of prokaryotes in environmental samples at high throughput. 相似文献
2.
Crop performance, nitrogen and water use in flooded and aerobic rice 总被引:11,自引:0,他引:11
P. Belder B. A. M. Bouman J. H. J. Spiertz S. Peng A. R. Castañeda R. M. Visperas 《Plant and Soil》2005,273(1-2):167-182
Irrigated aerobic rice is a new system being developed for lowland areas with water shortage and for favorable upland areas with access to supplementary irrigation. It entails the cultivation of nutrient-responsive cultivars in nonsaturated soil with sufficient external inputs to reach yields of 70–80% of high-input flooded rice. To obtain insights into crop performance, water use, and N use of aerobic rice, a field experiment was conducted in the dry seasons of 2002 and 2003 in the Philippines. Cultivar Apo was grown under flooded and aerobic conditions at 0 and at 150 kg fertilizer N ha–1. The aerobic fields were flush irrigated when the soil water potential at 15-cm depth reached –30 kPa. A 15N isotope study was carried out in microplots within the 150-N plots to determine the fate of applied N. The yield under aerobic conditions with 150 kg N ha–1 was 6.3 t ha–1 in 2002 and 4.2 t ha–1 in 2003, and the irrigation water input was 778 mm in 2002 and 826 mm in 2003. Compared with flooded conditions, the yield was 15 and 39% lower, and the irrigation water use 36 and 41% lower in aerobic plots in 2002 and 2003, respectively. N content at 150 kg N ha–1 in leaves and total plant was nearly the same for aerobic and flooded conditions, indicating that crop growth under aerobic conditions was limited by water deficit and not by N deficit. Under aerobic conditions, average fertilizer N recovery was 22% in both the main field and the microplot, whereas under flooded conditions, it was 49% in the main field and 36% in the microplot. Under both flooded and aerobic conditions, the fraction of 15N that was determined in the soil after the growing season was 23%. Since nitrate contents in leachate water were negligible, we hypothesized that the N unaccounted for were gaseous losses. The N unaccounted for was higher under aerobic conditions than under flooded conditions. For aerobic rice, trials are suggested for optimizing dose and timing of N fertilizer. Also further improvements in water regime should be made to reduce crop water stress. 相似文献
3.
Zusammenfassung Um die Abhängigkeit der erythropoietischen Zellformen von ihrer Stellung im Generationszyklus (G1, S und G2) zu untersuchen, wurde das Knochenmark von vier Normalpersonen mit der Kombination von zytophotometrischer DNS-Bestimmung (Feulgen-Photometrie) und autoradiographischer Technik mit 3H-TdR (in vitro) untersucht. Die Zellen wurden vor dieser Untersuchung in den nach Pappenheim gefärbten Ausstrichen differenziert.Sowohl in der Gruppe der basophilen Erythroblasten (E1-E3) als auch bei den polychromatischen Normoblasten (E4) wurde eine postmitotische (G1) und eine prämitotische Ruhephase (G2) nachgewiesen. Beide Zellgruppen waren zu ca. 65% mit3H-TdR markiert (S).Unter den basophilen Erythroblasten war bei E1 eine G2-Phase, jedoch keine G1-Phase nachweisbar. Demgegenüber fand sich bei E3 eine ausgeprägte G1-Phase, hingegen keine G2-Phase. Bei E2 war sowohl eine G1-Phase als auch eine G2-Phase erkennbar. Nach diesen Befunden stellen die Erythroblasten E1-E3 keine Zellgruppen mit jeweils vollständigem Generationszyklus dar, sondern sind als ein Zellkompartment zu verstehen, in dem die G1-Phase vorwiegend durch die kleineren Zellen, die zytologisch die Merkmale der basophilen Normoblasten besitzen, und die G2-Phase vorwiegend durch die größeren Zellen vom Typ der Proerythroblasten und Makroblasten repräsentiert wird.
Comparative morphological and cytophotometric-autoradiographical investigation of erythropoiesis in the human
Summary In the different types of normal human nucleated red cells the stages of the cell cycle (G1, S and G2) were investigated by combined application of the cytophotometric determination of the DNA content (Feulgen photometry) and of autoradiographic labelling using 3H-TdR in vitro. The individual cells were identified in Pappenheim stain.In the basophilic erythroblasts (E1-E3) as well as in the polychromatic erythroblasts (E4) about 62–65% of the cells were labelled (S). The unlabelled cells partly were diploid and partly were tetraploid, representing G1 and G2. The oxyphilic erythroblasts (E5) mostly were diploid and unlabelled (G1).Within the basophilic erythroblasts G1 was demonstrated mainly in E3, and G2 was demonstrated mainly in E1. In E2, G1 as well as G2 were present. The results indicate that all basophilic erythroblasts belong to one cell compartment, in which G1 is represented by the smaller cells commonly subclassified as basophilic normoblasts and G2 is represented by the large cells usually called proerythroblasts and macroblasts.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
4.
A flexible sigmoid function of determinate growth 总被引:10,自引:0,他引:10
A new empirical equation for the sigmoid pattern of determinate growth, 'the beta growth function', is presented. It calculates weight (w) in dependence of time, using the following three parameters: t(m), the time at which the maximum growth rate is obtained; t(e), the time at the end of growth; and w(max), the maximal value for w, which is achieved at t(e). The beta growth function was compared with four classical (logistic, Richards, Gompertz and Weibull) growth equations, and two expolinear equations. All equations described successfully the sigmoid dynamics of seed filling, plant growth and crop biomass production. However, differences were found in estimating w(max). Features of the beta function are: (1) like the Richards equation it is flexible in describing various asymmetrical sigmoid patterns (its symmetrical form is a cubic polynomial); (2) like the logistic and the Gompertz equations its parameters are numerically stable in statistical estimation; (3) like the Weibull function it predicts zero mass at time zero, but its extension to deal with various initial conditions can be easily obtained; (4) relative to the truncated expolinear equation it provides more reasonable estimates of final quantity and duration of a growth process. In addition, the new function predicts a zero growth rate at both the start and end of a precisely defined growth period. Therefore, it is unique for dealing with determinate growth, and is more suitable than other functions for embedding in process-based crop simulation models to describe the dynamics of organs as sinks to absorb assimilates. Because its parameters correspond to growth traits of interest to crop scientists, the beta growth function is suitable for characterization of environmental and genotypic influences on growth processes. However, it is not suitable for estimating maximum relative growth rate to characterize early growth that is expected to be close to exponential. 相似文献
5.
An economic analysis of sweet sorghum cultivation for ethanol production in North China 总被引:2,自引:0,他引:2
Huihui Liu Lantian Ren Huub Spiertz Yongbin Zhu Guang Hui Xie 《Global Change Biology Bioenergy》2015,7(5):1176-1184
Sweet sorghum [Sorghum bicolor (L.) Moench] is a promising non‐food energy crop. The objective of this study was to determine the economic costs and input sensitivity of sweet sorghum compared to cotton, maize, and sunflower, at two saline‐alkali sites in Shandong (Wudi County) and Inner Mongolia (Wuyuan County) provinces of China. The data were collected quantitatively based on a face‐to‐face interview with 100 and 67 sweet sorghum growers at the two sites, respectively. The sweet sorghum grown at Wudi had lower external input (5469 CNY ha?1), higher net return (7305 CNY ha?1) and benefit‐cost ratio (2.36) than its reference crop, cotton (18 454 CNY ha?1; 3615 CNY ha?1; 1.24). At Wuyuan, the sweet sorghum showed contrasting economic performance (19 541 CNY ha?1; ?3438 CNY ha?1; 0.91), which was largely because of the higher labor costs compared to sunflower (10 896 CNY ha?1; 15 133 CNY ha?1; 2.49); and maize (9108 CNY ha?1; 14 760 CNY ha?1; 2.76). The productivity of sweet sorghum per unit of external input costs (kg CNY?1) was 13.12 for Wudi and only 3.26 for Wuyuan. Based on the Cobb‐Douglas production function, the external inputs of diesel and seed had a significantly positive impact on the profitability of sweet sorghum at Wudi but not at Wuyuan. However, the costs of irrigation and film cover were significantly negative. The energy crop, sweet sorghum, showed a better return to scale on investment than cotton and sunflower. 相似文献
6.
Relay intercropping of wheat and cotton is practiced on a large scale in China. Winter wheat is thereby grown as a food crop
from November to June and cotton as a cash crop from April to October. The crops overlap in time, growing as an intercrop,
from April till June. High levels of nitrogen are applied. In this study, we analyzed the N-economy of the monocultures of
cotton and wheat, and of four relay intercropping systems, differing in number of rows per strip of cotton or wheat. Field
experiments were carried out from 2001/02 to 2003/04 in the Yellow River region in China. We quantified the nitrogen uptake
and nitrogen use efficiency of wheat and cotton in relay intercropping systems to test if intercrops are more resource use
efficient in comparison to monocrops. Nitrogen (N) yields of wheat per unit area in the four intercropping systems were lower
than in the monocrop, which ranged from 203 to 288 kg ha−1. The total N-uptake per unit biomass was similar between wheat in mono- and intercrops. On average, the N-yield of cotton
per unit area was lower in intercrops than in monocrops, which ranged from 110 to 127 kg ha−1, but the total N-uptake per unit biomass was higher in intercropped cotton, as dry matter production was reduced to a greater
extent by intercropping than N-uptake. The N-uptake of cotton was diminished during the intercropping phase, but recovered
partially during later growth stages. The physiological nitrogen use efficiency (IE) of wheat was not much affected by intercropping,
but it was reduced in cotton, due to delayed flowering and less reproductive growth. Total N-efficiency of the system was
assessed by comparing the relative nitrogen yield total (RNT), i.e. the sum of the ratio’s of total N-uptake by a component
crop in the intercrop relative to the N-uptake in the monocrop, to the relative yield total. RNT ranged from 1.4 to 1.7, while
the relative yield total (RYT) ranged from 1.3 to 1.4, indicating that intercrops used more nitrogen per unit production than
monocrops. An analysis of the crop nitrogen balance showed that the nitrogen surplus of sole crops amounted to 220 kg ha−1 for wheat and 140 kg ha−1 for cotton, while in the intercropping systems, the annual N surplus exceeded 400 kg ha−1. Conventional N-management in intercrops thus results in high N-surpluses that pose an environmental risk. The N management
could be improved by means of a demand-based rate and timing of N applications. 相似文献
7.
8.
Genotype and Planting Density Effects on Rooting Traits and Yield in Cotton (Gossypium hirsutum L,) 总被引:2,自引:0,他引:2
Li-Zhen Zhang Bao-Guo Li Gen-Tu Yan Wopke van der Werf JHJ Spiertz Si-Ping Zhang 《植物学报(英文版)》2006,48(11):1287-1293
Root density distribution of plants is a major Indicator of competition between plants and determines resource capture from the solh This experiment was conducted in 2005 at Anyang, located in the Yellow River region, Henan Province, China. Three cotton (Gossyplum hlrsutum L.) cultivars were chosen: hybrid Btcultlvar CRI46, conventional Btcultlvars CRI44 and CRI45. Six planting densities were designed, ranging from 1.5 to 12.0 plants/m^2. Root parameters such as surface area, diameter and length were analyzed by using the DT-SCAN Image analysis method. The root length density (RLD), root average diameter and root area Index (RAI), root surface area per unit land area, were studied. The results showed that RLD and RAI differed between genotypes; hybrid CRI46 had significantly higher (P 〈0.05) RLD and RAI values than conventlonal cultlvars, especially under low planting densities, less than 3.0 plants/m^2. The root area index (RAI) of hybrid CRI46 was 61% higher than of CRI44 and CRI45 at the flowering stage. The RLD and RAI were also significantly different (P = 0.000) between planting densities. The depth distribution of RAI showed that at Increasing planting densities RAI was Increasingly distributed in the soil layers below 50 cm. The RAI of hybrid CRI46 was for all planting densities, obviously higher than other cultivars during the flowering and boll stages. It was concluded that the hybrid had a strong advantage in root maintenance preventing premature senescence of roots. The root diameter of hybrid CRI46 had a genetically higher root diameter at planting densities lower than 6.0 plants/m^2. Good associations were found between yield and RAI In different stages. The optimum planting density ranged from 4.50 plants/m^2 to 6.75 plants/m^2 for conventional cultlvars and around 4.0-5.0 plants/m^2 for hybrids. 相似文献
9.
QJ Voorham B Carvalho AJ Spiertz B Claes S Mongera NC van Grieken H Grabsch M Kliment B Rembacken MA van de Wiel P Quirke CJ Mulder D Lambrechts M van Engeland GA Meijer 《PloS one》2012,7(7):e41963
Background
Flat adenomas are a subgroup of colorectal adenomas that have been associated with a distinct biology and a more aggressive clinical behavior compared to their polypoid counterparts. In the present study, we aimed to compare the mutation spectrum of 14 cancer genes, between these two phenotypes.Methods
A consecutive series of 106 flat and 93 polypoid adenomas was analyzed retrospectively for frequently occurring mutations in “hot spot” regions of KRAS, BRAF, PIK3CA and NRAS, as well as selected mutations in CTNNB1 (β-catenin), EGFR, FBXW7 (CDC4), PTEN, STK11, MAP2K4, SMAD4, PIK3R1 and PDGFRA using a high-throughput genotyping technique. Additionally, APC was analyzed using direct sequencing.Results
APC mutations were more frequent in polypoid adenomas compared to flat adenomas (48.5% versus 30.3%, respectively, p = 0.02). Mutations in KRAS, BRAF, NRAS, FBXW7 and CTNNB1 showed similar frequencies in both phenotypes. Between the different subtypes of flat adenomas (0-IIa, LST-F and LST-G) no differences were observed for any of the investigated genes.Conclusion
The lower APC mutation rate in flat adenomas compared to polypoid adenomas suggests that disruption of the Wnt-pathway may occur via different mechanisms in these two phenotypes. Furthermore, in contrast to previous observations our results in this large well-defined sample set indicate that there is no significant association between the different morphological phenotypes and mutations in key genes of the RAS-RAF-MAPK pathway. 相似文献10.
Laura A. E. Hughes Piet A. van den Brandt Adriaan P. de Bru?ne Kim A. D. Wouters Sarah Hulsmans Angela Spiertz R. Alexandra Goldbohm Anton F. P. M. de Goeij James G. Herman Matty P. Weijenberg Manon van Engeland 《PloS one》2009,4(11)