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991.
Chromosome segment substitution lines (CSSL) consist of a battery of near-isogenic lines that have been developed and cover the entire genome of some crops. With the exception of one homozygous chromosome segment transferred from a donor parent, the remaining genome of each CSSL line is the same as the recipient parent. It is an ideal material for genome research and particularly QTL mapping. In the present study, we first developed one set of CSSL lines using G hirsutum acc. TM-1 (the genetic standard), as the recipient parent and G barbadense cv. Hai7124 as the donor parent using molecular assistedlselection in BC5S1-3 generations. The CSSL consisted of 330 different lines, in which 1-4 different lines had the same or overlapping substituted segments. The genetic length of the substituted segments covered 5271.9 cM with an average segment distance of 10.9 cM, 1.5 times the total genetic length of Upland cotton (3514.6 cM). The substituted segments of each line varied in length, ranging from 3.5 cM for the shortest segment to 23.2 cM in the longest segment. Our CSSL have not yet to cover the entire tetraploid cotton genome, due to the absence of some donor parent interval segments. 相似文献
992.
Nickel accumulated in midugt of Spodoptera litura Fabricius could induce the expression of metallothionein, one of the most important detoxification proteins in organisms. In the present study, the effects of dietary nickel on the activities of detoxification enzymes, such as carboxylesterase (CarE) and giutathione S-transferase (GST) in the midgut of S. litura larvae have been studied to get an understanding of the detoxification mechanisms of S. litura larvae to excessive nickel. Results showed that CarE activities in the midgut of the 5th instar larvae decreased at lower levels of nickel (≤5 mg/kg), while increased with increasing nickel doses at higher levels of nickel (≥10 mg/kg) exposure in successive 3 generations. CarE activities of the 6th instar larvae were also characterized as inhibited at low levels of nickel exposure, and improved at higher levels in the 1st generation. CarE activities of 6th instar larvae in the 2nd and 3rd generations were all lower than that in control. However, GST activities in the midgut of the 5th and 6th instar larvae all increased with increasing nickel doses (1 --20 mg/kg) in diets. 相似文献
993.
NO (nitric oxide), known as a key signal molecule in plant, plays important roles in regulation of stomatal movement. In this study, microtubule dynamics and its possible mechanism in the NO signal pathway were investigated. The results were as follows: (i) In vivo stomatsl aperture assays revealed that both vinblastine (microtubule-disrupUng drug) and SNP (exogenous NO donor) prevented stomatsl opening in the light, and vinblastine even could enhance the inhibitory effect of SNP, whereas tsxol (a microtubule-stsbilizing agent) was able to reduce this effect; (ii) microtubules in the opening Arabi-dopsis guard cells expressing GFP:a-tubulin-6 (AtGFP:a-tubulin-6) were organized in parallel, straight and dense bundles, radiating from the ventral side to the dorsal side, and most of them were localized perpendicularly to the ventral wall; (iii) under the same environmental conditions, treated with SNP for 30 min, the radial arrays of microtubules in guard cells began to break down, twisted partially and be- came oblique or exhibited a random pattern; (iv) furthermore, the involvement of cytosolic Ca^2+ in this event was tested. Stomatal aperture assays revealed that BAPTA-AM (a chelator of Ca^2+) greatly suppressed the effect of NO on stomatal closure; however, it did not show the same function on stomatal closure induced by vinblastine. When BAPTA-AM was added to the SNP-pretreated solution, the SNP-induced disordered microtubulue cytoskeleton in guard cells underwent rearrangement in a time-dependent manner. After 30 min of treatment with BAPTA-AM, the cortical microtubules resumed the original radial distribution, almost the same as the control. All this indicates that NO may promote rearrangement of microtubule cytoskeleton via elevation of [Ca^2+]cyt (free Ca^2+ concentration in the cytoplasm), finally leading to stomatsl closure. 相似文献
994.
Plants are exposed to many potentially pathogenic microbes in the environment, but each species is only susceptible to a limited number of pathogens. The broad resistance is referred to as nonhost resistance. To date, little is known about the underlying mechanism of nonhost resistance and the signaling transduction process. Here we describe a simple method for isolating Arabidopsis nonhost resistance mutants against a nonadapted bacterial pathogen. A RAP2.6 promoter-driven LUC reporter system was developed to replace the tedious bacterial growth assay during the primary screening. The RAP2.6-LUC reporter gene is normally induced by the virulent bacterium Pseudomonas syringae pv tomato but not the nonadapted bacterium P. syringae pv phaseolicola. By using this method we iso- lated 4 mutants displaying strong reporter activity in response to P. syringae pv phaseolicola, which were characterized in some details, ebsl, ebs2, ebs3, and ebs4 (enhanced bacterial susceptibility) were compromised in resistance against P. syringae pv phaseolicola and/or P. syringae pv tomato. In addition, ebs4 showed enhanced hypersensitive response to the incompatible bacterium P. syringae pv tomato (avrB). These results demonstrated that the method is suited for large scale screening for nonhost resistance mutants. 相似文献
995.
Tiling array technology was improved from microarray technology. Over the past five years, tiling array has become an important tool for gathering genome information. Its features of high density and high throughput allow people to probe into life from the whole-genome level. This paper is a survey of tiling array technology and its applications. In addition, some typical algorithms for identifying expressed probe signals are described and compared. 相似文献
996.
The intrinsic synchronization, multi-color outputs and related carrier-envelope phases (CEP) among pulses bring advantages to synchronously pumped femtosecond optical parametric oscillators and the pumping sources for broadband frequency comb generation and ultrashort waveform coherent syn-thesis. In this paper, we discuss our latest research results in this field, which cover the following as-pects: the phase relationship and energy conservation law in an OPO and related experimental verifi-cation; control of the pumping Ti-sapphire femtosecond laser's CEP by self-referencing technology, and its repetition-rate locking by piezoelectric transducer (PZT); CEP locking of the pulses from the OPO by beating the non-phase-matched visible outputs against pump supercontinuum to obtain a driving signal for a fast PZT on the OPO end mirror; the generation of a broadband frequency comb spanning from 400 nm to 2.4 μm with 1.2 kHz bandwidth; and the realization of coherent interference between phase controlled pump pulses and signal second harmonic pulses. 相似文献
997.
Transmission of oxygen isotope signals of precipitation-soil water-drip water and its implications in Liangfeng Cave of Guizhou,China 总被引:4,自引:0,他引:4
According to systemically monitoring results of oxygen (hydrogen) isotope compositions of precipitation, soil waters, soil CO2, cave drip waters and their corresponding speleothems in Liangfeng Cave (LFC) in Guizhou Province, Southwest China, it is found that local precipitation is the main source of soil waters and drip waters, and that the amplitudes of those δ18O values of three waters (precipitation, soil water and drip water) decrease in turn in the observed year, which are 0‰ to -10‰, -2‰ to -9‰ and -6‰ to -8‰, respectively. Moreover, the δ18O values for three waters show a roughly simultaneous variation, namely, that those values are lighter in the rainy seasons, weightier in the dry seasons, and that the average δ18O value of drip waters is about 0.3‰ weightier than that of precipitation, which is modified by surface evaporation processes. We also find that oxygen isotope equilibrium is reached or neared in the formation processes of speleothems in LFC system, and that it is feasible to reconstruct paleotemperature and paleoprecipitation by using δ18O values of speleothems. However, it should be noted that surface evaporation would affect the oxygen isotope values in the study area. 相似文献
998.
Petrographic and geochemical characterization of seep carbonate from Alaminos Canyon,Gulf of Mexico 总被引:3,自引:1,他引:2
Seep carbonates were collected from the Alaminos Canyon lease area, Gulf of Mexico. The carbonates are present as slabs and blocks. Bivalve shell and foraminifer are the dominant bioclasts in carbonate. Pores are common and usually filled with acicular aragonite crystals. XRD investigation shows that aragonite is the dominate mineral (98%). Peloids, clotted microfabirc and botryoidal aragonite are developed in carbonate and suggest a genesis linked with bacterial degradation of the hydrocarbons. The δ^13C value of bioclasts in carbonate is from -4.9‰ to -0.6‰, indicating that the carbon source is mainly from sea water as well as the small portion incorporation of the seep hydrocarbon. The microcrystalline and sparite aragonite shows the δ^13C value from -31.3‰ to -23.4‰, suggesting that their carbon is derived mainly from microbial degradation of crude oil. ^14C analyses give the radiocarbon age of about 10 ka. Rare earth elements (REE) analyses of the 5% HNO3-treated solution of the carbonates show that the total REE content of the carbonates is low, that is from 0.752 to 12.725 μg·g^-1. The shale-normalized REE patterns show significantly negative Ce anomalies. This suggests that cold seep carbonate is most likely formed in a relatively aerobic environment. 相似文献
999.
Using three kinds of over 100-year sea surface temperature (SST) datasets as well as three-dimensional wind data from NCEP/NCAR, this paper documents the decadal variability of the Indian Ocean Dipole (IOD)-EI Nino/Southern Oscillation (ENSO) relationship. During 1948--1969, positive (negative) IOD and warm (cold) ENSO events were more independent of each other. But after 1970, they tended to occur in the same year. ENSO would influence the whole life span of IOD, and IOD also affects the developing phase of ENSO. Considering the climatological background SST, low-level winds and also equatorial vertical circulations, it is revealed that the decadal variability of the IOD-ENSO relationship may be caused by the enhanced Walker circulation with increased rising motion over the Maritime Continent after 1970. Warmer SST around the Maritime Continent gives rise to anomalous low-level convergence and intensified convection there, which apparently increases the SST linkage between the eastern Indian Ocean and the western Pacific and thereby the interaction between the IOD and ENSO event. 相似文献
1000.
There are many sediment trapping reservoirs in the Hill Loess Plateau. The Huangtuwa small catchment is selected as a research field where samples were collected in a sediment deposit profile with a vertical length of 12.73 m. By the variation of fine particle content and pollen concentration, 54 flood couples were identified. Taking the freeze-thawing disturbed texture as the sign of the latest flood couple in a year, it is ascertained that those 54 floods should happen in 31 years. Using pyramid volume calculation formula, the sediment yields of flood ranged between 716-30376 t· km^-2, The average sediment yield was 7106 t· km^-2, The annual sediment yields varied between 968-55579 t· (km^2· a)^-1, and the average value is 12629 t· (km^2· a)^-1. Compared with the modern annual sediment discharge of the Huaining River, the erosion rate in the Huangtuwa region 450 years ago was similar to the modern erosion rate. In the period from the 27th year to the 31st year, the average annual sediment yield increased sharply to 31309 t· (km^2· a)^-1. It implied that re-reclamation of the abandoned land in the catchment since the landslide disaster, where vegetation had rehabilitated already, caused very severe soil erosion in the catchment. 相似文献