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991.
992.
Russell W. Jessup 《In vitro cellular & developmental biology. Plant》2009,45(3):282-290
The biofuel industry is rapidly growing because of increasing energy demand and diminishing petroleum reserves on a global
scale. A multitude of biomass resources have been investigated, with high-yielding, perennial feedstocks showing the greatest
potential for utilization as advanced biofuels. Government policy and economic drivers have promoted the development and commercialization
of biofuel feedstocks, conversion technologies, and supply chain logistics. Research and regulations have focused on the environmental
consequences of biofuels, greatly promoting systems that reduce greenhouse gas emissions and life-cycle impacts. Numerous
biofuel refineries using lignocellulosic feedstocks and biomass-based triglycerides are either in production or pre-commercial
development phases. Leading candidate energy crops have been identified, yet require additional efforts to realize their full
potential. Advanced biofuels, complementing conventional biofuels and other renewable energy sources such as wind and solar,
provide the means to substantially displace humanity’s reliance on petroleum-based energy. 相似文献
993.
Feng Wang Xue-Rong Xiong Chun-Zhao Liu 《In vitro cellular & developmental biology. Plant》2009,45(3):342-349
With rapid economic development, energy consumption in China has tripled in the past 20 yr, exceeding 2.4 billion tons of
standard coal in 2006. The search for new green energy as substitutes for the nonrenewable energy resources has become an
urgent task. China has a variety of climates and is rich in potential biofuel plant species. Corn and cassava are used as
the main raw materials for bioethanol production in China. At the end of 2005, bioethanol productivity had increased to 1.02
million tons produced by four companies, and bioethanol-blended petrol accounted for 20% of the total petrol consumption in
China. According to the Mid- and Long-term Development Plan for Renewable Energy, the consumption of biodiesel in China will
reach 0.2 million tons in 2010 and 2.0 million tons in 2020. This review is intended to provide an introduction to the distribution
and development of biofuel crops and biofuel industry in China. 相似文献
994.
An hydroponic culture was conducted to investigate the effect of saline stress on the essential oil and fatty acid composition
of Tunisian coriander (Coriandrum sativum L.) roots. Ten days old coriander seedlings were treated during 3 weeks with different NaCl concentrations (0, 25, 50 and
75 mM). Roots volatile components and fatty acids were analyzed. The essential oil yield was 0.06% in the control, on the
basis of dry matter weight, and did not changed at low concentration (25 mM), while it increased significantly with increasing
NaCl concentrations to reach 0.12 and 0.21% at 50 and 75 mM NaCl, respectively. The major volatile component was (E)-2-dodecenal with 52% of total essential oil constituents, followed by decanal, dodecanal, (E)-2-tridecenal and (E)-2-dodecenal. Further, the amount of these compounds was affected differently by the NaCl level. Total fatty acid amount
of coriander roots increased significantly only with 50 and 75 mM NaCl. Three major fatty acids: linoleic (43%), oleic (25.5%)
and palmitic (21.6%) were identified. Linoleic acid amount remains unchanged at 25 mM, while it increased with raising NaCl
concentrations. However, oleic acid amount decreased only at 25 mM and no effect was observed at 50 and 75 mM. Fatty acid
percentages were differently affected by salt. The oleic/linoleic ratio was reduced with raising NaCl concentrations. 相似文献
995.
G. Mulderij B. Mau L. N. de Senerpont Domis A. J. P. Smolders E. Van Donk 《Aquatic Ecology》2009,43(2):305-312
The aquatic macrophyte Stratiotes aloides Linnaeus, which has recently received attention in studies on allelopathy, has been shown to suppress phytoplankton growth.
In the Netherlands, S. aloides often co-occurs with floating filamentous algae. However, filamentous algae are generally absent in close proximity to S. aloides, resulting in gaps in filamentous algae mats. We analyzed whether those gaps may be caused by allelopathic substances excreted
by S. aloides or by nutrient depletion. We studied in a field survey the colonization of natural S. aloides by filamentous algae and determined in situ nutrient concentrations in natural S. aloides stands. To analyze the relative importance of allelopathy and nutrient competition in the interaction between S. aloides and filamentous algae, we carried out field experiments. Introduction of artificial (non-allelopathic) plants in natural
S. aloides stands enabled us to compare the colonization by filamentous algae of both Stratiotes sp. and artificial plants. The filamentous algae were absent in close vicinity to S. aloides. Significantly lower concentrations of ortho-phosphate and potassium were observed close to S. aloides as compared with the filamentous algae. In the field experiments the artificial plants were rapidly colonized by filamentous
algae, mainly Cladophera Kützing and Spirogyra Link, while all natural plants remained free of such algae. Additionally, most nutrient concentrations did not significantly
differ in the proximity of artificial or natural stands of S. aloides. The concentrations of the major growth-limiting nutrients, phosphate and nitrate, were significantly higher and nonlimiting
in natural Stratiotes stands. Our main conclusion is that, although allelopathic interactions between S. aloides and filamentous algae do occur under natural conditions, nutrient competition between the two can also be an important factor. 相似文献
996.
Haidong Ding Aying Zhang Jinxiang Wang Rui Lu Hong Zhang Jianhua Zhang Mingyi Jiang 《Planta》2009,230(2):239-251
Mitogen-activated protein kinase (MAPK) cascades have been shown to be important components in abscisic acid (ABA) signal
transduction pathway. In this study, a 46 kDa MAPK (p46MAPK) induced by ABA was partially purified from maize (Zea mays) by Q-Sepharose FF, Phenyl-Sepharose FF, Resource Q, Mono QTM 5/50 GL, poly-l-lysine-agarose, and Superdex 75 prep-grade columns, and was identified as ZmMAPK5 (gi|4239889) by the matrix-assisted laser
desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) mass spectrometry. Furthermore, the kinase showed optimal
activity at pH 8.0, 30°C, and 10 mM MgCl2; the K
m
for myelin basic protein (MBP) substrate and ATP were 0.13 μg μl−1 and 62 μM, respectively. MBP was the preferred substrate, of which the threonine residue was phosphorylated. Finally, the
kinase was found to respond to diverse extracelluar stimuli. These results enable us to further reveal the function of the
ZmMAPK5 in ABA signaling.
The authors Haidong Ding and Aying Zhang contributed equally to the work. 相似文献
997.
998.
Lörinczi E Napp J Contreras-Jurado C Pardo LA Stühmer W 《European biophysics journal : EBJ》2009,38(3):279-284
The ether-à-go-go potassium channels hEag1 and hEag2 are highly homologous. Even though both possess identical voltage-sensing
domain S4, the channels act differently in response to voltage. Therefore we asked whether transmembrane domains other than
the voltage sensor could contribute to the voltage-dependent behaviour of these potassium channels. For this chimaeras were
created, in which each single transmembrane domain of hEag1 was replaced by the corresponding segment of hEag2. The voltage-dependent
properties of the chimaeras were analysed after expression in Xenopus laevis oocytes using the two-electrode voltage-clamp method. By this we found, that only the mutations in transmembrane domains
S5 and S6 are able to change the voltage sensitivity of hEag1 by shifting the half-activation potential (V
50) to values intermediate between the two wild types. Moreover, the presence of Mg2+ has strong effects on the voltage sensitivity of hEag2 shifting V
50 by more than 50 mV to more positive values. Interestingly, despite the identical binding site Mg2+ showed only little effects on hEag1 or the chimaeras. Altogether, our data suggest that not only transmembrane spanning regions,
but also non-membrane spanning regions are responsible for differences in the behaviour of the hEag1 and hEag2 potassium channels.
EBSA Satellite meeting: Ion channels, Leeds, July 2007. 相似文献
999.
Rym Zitari-Chatti Noureddine Chatti Domenico Fulgione Immacolata Caiazza Gennaro Aprea Ali Elouaer Khaled Said Teresa Capriglione 《Genetica》2009,136(3):439-447
In this study we analysed mitochondrial DNA variation in Penaeus kerathurus prawns collected from seven locations along a transect across the Siculo–Tunisian region in order to verify if any population
structuring exists over a limited geographical scale and to delineate the putative transition zone with sufficient accuracy.
Partial DNA sequences of COI and 16S genes were analysed. In contrast to the highly conservative 16S gene, the COI sequences
exhibited sufficient diversity for population analysis. The COI gene revealed low levels of haplotype and nucleotide diversities.
The size of the annual landings of this commercial species suggests large population sizes. Hence, the low genetic diversity
detected in this study could indicate a possible reduction in effective population sizes in the past. We detected significant
genetic differentiation between eastern and western populations likely due to restricted gene flow across the Siculo–Tunisian
boundary. We discuss the different evolutionary forces that may have shaped the genetic variation and suggest that the genetic
divide is probably maintained by present-day dispersal limitation.
R. Zitari-Chatti and N. Chatti are contributed equally to the work. 相似文献
1000.
Diel variation of phytoplankton functional groups in a subtropical reservoir in southern Brazil during an autumnal stratification period 总被引:1,自引:0,他引:1
A knowledge of diel variation and the vertical distribution of phytoplankton communities may contribute to a better understanding
of the driving factors of key species. Applying functional-group classification provides important information on the causes
of species selection in the pelagic community. The diel variation of phytoplankton functional groups was analysed during an
autumnal stratification period with the aim of understanding their changes in the vertical position related to light, mixing
regime and grazing pressure. Phytoplankton and zooplankton communities were sampled every 4 h during a 24-h period in a vertical
profile in a subtropical meso-eutrophic reservoir. Strong stratification during a 24-h cycle and a mixed clear epilimnion
with partial atelomixis marked the autumn season in the Faxinal reservoir, southern Brazil. The highest phytoplankton densities
and biomass were found during the second part of the day, a general pattern reported in the literature, and may be explained
by zooplankton dynamics. During the 24-h cycle, phytoplankton functional groups lacking a self-regulating capacity and those
able to regulate their vertical position were vertically segregated in the lake. The diel behaviour of both groups was driven
by the mixing regime (including atelomixis), light and zooplankton grazing pressure. 相似文献