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951.
M. H. Huesemann J. Van Wagenen T. Miller A. Chavis S. Hobbs B. Crowe 《Biotechnology and bioengineering》2013,110(6):1583-1594
A microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient‐replete conditions in photobioreactors or outdoor ponds. Growth is modeled by first estimating the light attenuation by biomass according to Beer‐Lambert's Law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model uses only two physical and two species‐specific biological input parameters, all of which are relatively easy to determine: incident light intensity, culture depth, as well as the biomass light absorption coefficient and the specific growth rate as a function of light intensity. Roux bottle culture experiments were performed with Nannochloropsis salina at constant temperature (23°C) at six different incident light intensities (10, 25, 50, 100, 250, and 850 µmol/m2 s) to determine both the specific growth rate under non‐shading conditions and the biomass light absorption coefficient as a function of light intensity. The model was successful in predicting the biomass growth rate in these Roux bottle batch cultures during the light‐limited linear phase at different incident light intensities. Model predictions were moderately sensitive to minor variations in the values of input parameters. The model was also successful in predicting the growth performance of Chlorella sp. cultured in LED‐lighted 800 L raceway ponds operated in batch mode at constant temperature (30°C) and constant light intensity (1,650 µmol/m2 s). Measurements of oxygen concentrations as a function of time demonstrated that following exposure to darkness, it takes at least 5 s for cells to initiate dark respiration. As a result, biomass loss due to dark respiration in the aphotic zone of a culture is unlikely to occur in highly mixed small‐scale photobioreactors where cells move rapidly in and out of the light. By contrast, as supported also by the growth model, biomass loss due to dark respiration occurs in the dark zones of the relatively less well‐mixed pond cultures. In addition to screening novel microalgae strains for high biomass productivities, the model can also be used for optimizing the pond design and operation. Additional research is needed to validate the biomass growth model for other microalgae species and for the more realistic case of fluctuating temperatures and light intensities observed in outdoor pond cultures. Biotechnol. Bioeng. 2013; 110: 1583–1594. © 2012 Wiley Periodicals, Inc. 相似文献
952.
953.
MOHANNAD ISMAIL JOAN VAN BAAREN THIERRY HANCE JEAN‐SEBASTIEN PIERRE PHILIPPE VERNON 《Ecological Entomology》2013,38(4):355-363
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954.
955.
《Chronobiology international》2013,30(5):853-862
In a previous study we found that daytime exposure to bright as compared to dim light exerted a beneficial effect on the digestion of the evening meal. This finding prompted us to examine whether the digestion of the evening meal is also affected by evening light intensity. Subjects lived in light of 200 lux during the daytime (08:00–17:00 h) and took their evening meal at 17:00 h under 20 lux (evening dim‐light condition: 17:00–02:00 h) or 2000 lux (evening bright‐light condition: 17:00–02:00 h) until retiring at 02:00 h. Assessment of carbohydrate digestion of the evening meal was accomplished by a breath hydrogen test that is indicative of the malabsorption of dietary carbohydrate. Hydrogen excretion in the breath in the evening under the dim‐light condition was significantly less than under the bright‐light condition (p < 0.05). This finding is the opposite to that obtained in previous experiments in which subjects were exposed to the different intensities of light during the daytime, and indicates that the exposure to dim light in the evening exerts a better effect on carbohydrate digestion in the evening meal than does the exposure to bright light. 相似文献
956.
957.
Koji Muramoto Hiroshi Meguro Katura Tuzimura 《Bioscience, biotechnology, and biochemistry》2013,77(10):2059-2062
Fluoresceinisothiocyanate was applied to fluorescent labeling of protein for the determination of molecular weight by SDS Polyacrylamide gel electrophoresis. Proteins having molecular weight ranging from 15,000 to 70,000 were tested. The resolved FITC-labeled protein was eluted from the gel and was submitted to amino acid sequence analysis. 相似文献
958.
Bhaboklang Sohkhlet 《Indian journal of human genetics》2013,19(3):315-319
BACKGROUND:
In order to understand how selection is operating in the Gowda population, the index of opportunity for selection was calculated and the present findings were compared with some related findings from other South Indian (SI) populations.MATERIALS AND METHODS:
Crow (1958) and the modified method by Johnston and Kensinger (1971) were used for the present purpose.RESULTS AND DISCUSSION:
The index of total selection intensity (I) was found to be moderate taking into consideration the range for many Indian populations. Considering certain differences in fertility and mortality heritable, it appears that natural selection play an important role in shaping the genetic constitution of the Gowda population. Analysis of data indicates that the index due to fertility seems to contribute more towards selection than mortality. This trend might be because of better living condition and health-care system among the Gowdas which have a positive impact on the lower contribution of mortality for the evolution mechanism of the Gowda population through natural selection. 相似文献959.
以往种群空间格局的研究大多基于植株点位或株数(0维),极少针对植冠的投影盖度(2维)和生物量(3维,由植冠体积体现).目前对三者所体现的种群空间格局特征尚不清楚.本研究以古尔班通古特沙漠广布的小半灌木白茎绢蒿和准噶尔沙蒿种群为对象,测定每株的点位、投影盖度及地上生物量,通过GIS技术对坐标系进行6次尺度划分,利用聚集度分析、变异系数及其与尺度的幂函数关系,分析了3个参数的种群分布格局特征.结果表明: 在各尺度下,两种群的株数(白茎绢蒿0.5 m尺度除外)和生物量均为集群分布,聚集强度随尺度增加而增大;而投影盖度多为均匀分布(准噶尔沙蒿5 m和8 m尺度除外).随尺度增大,两种群各参数的变异系数均逐渐下降;株数的幂指数的绝对值(k值)高于投影盖度和生物量,且后两者无显著差异.白茎绢蒿各参数的k值均高于准噶尔沙蒿,可能与群落种间关系及个体大小有关.总之,株数和生物量的空间格局类型相似,而投影盖度和生物量具有近乎相同的格局复杂性和尺度变化特征. 相似文献
960.
间伐强度对秦岭南坡栓皮栎种子库及实生苗生长的影响 总被引:2,自引:0,他引:2
2010年8-11月和2011年8月,以秦岭南坡商洛地区近自然经营的不同间伐强度(30%、20%和10%)下的栓皮栎纯林为对象,分析了间伐4~5年后栓皮栎种子库的种子数量,实生苗的存活率和生长状况,及其与环境因子的关系.结果表明:与对照相比,间伐后第4年,间伐10%、20%和30%强度下种子库中的种子总数分别增加了2.0%、21.1%和34.8%,翌年1年生实生苗数量分别增加了28.5%、99.7%和122.2%;间伐5年后,间伐10%、20%和30%样地内实生苗的存活率分别提高了25.5%、235.7%和480.0%.间伐使林地的光照、温度、土壤水分和养分等环境因子发生变化,促进了各年龄段实生苗的高度、新梢生长量及叶面积指数的增长,且随间伐强度的增加,3项生长指标均增加.在郁闭度≥0.85的栓皮栎林,间伐强度30%(郁闭度保留0.6)最有利于栓皮栎种子萌芽和实生苗生长. 相似文献