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排序方式: 共有315条查询结果,搜索用时 15 毫秒
311.
Miyake N Chilton J Psatha M Cheng L Andrews C Chan WM Law K Crosier M Lindsay S Cheung M Allen J Gutowski NJ Ellard S Young E Iannaccone A Appukuttan B Stout JT Christiansen S Ciccarelli ML Baldi A Campioni M Zenteno JC Davenport D Mariani LE Sahin M Guthrie S Engle EC 《Science (New York, N.Y.)》2008,321(5890):839-843
Duane's retraction syndrome (DRS) is a complex congenital eye movement disorder caused by aberrant innervation of the extraocular muscles by axons of brainstem motor neurons. Studying families with a variant form of the disorder (DURS2-DRS), we have identified causative heterozygous missense mutations in CHN1, a gene on chromosome 2q31 that encodes alpha2-chimaerin, a Rac guanosine triphosphatase-activating protein (RacGAP) signaling protein previously implicated in the pathfinding of corticospinal axons in mice. We found that these are gain-of-function mutations that increase alpha2-chimaerin RacGAP activity in vitro. Several of the mutations appeared to enhance alpha2-chimaerin translocation to the cell membrane or enhance its ability to self-associate. Expression of mutant alpha2-chimaerin constructs in chick embryos resulted in failure of oculomotor axons to innervate their target extraocular muscles. We conclude that alpha2-chimaerin has a critical developmental function in ocular motor axon pathfinding. 相似文献
312.
RAPD markers efficiently distinguish heterogenous populations of wild potato (Solanum) 总被引:1,自引:0,他引:1
Genetic characterization of germplasm is important for setting objective guidelines for conservation. One common problem found in genebanks is determining the value of populations with insufficient or unreliable data regarding their geographic origin. In this study, a genetic analysis based on RAPD markers was conducted to characterize a `mystery' population of Solanum sucrense, a polysomic tetraploid potato (2n=4x=48), for which adequate documentation was lacking. The comparative analysis of genetic similarities between this mystery population and each one of 30 other S. sucrense populations in the genebank revealed that all populations within this species, including the mystery population, are significantly different from being duplicates, and are therefore worthy of separate conservation. RAPD markers also distinguished the mystery population from closely related tetraploid species S. oplocense, S. gourlayi and S. tuberosum ssp. andigena, suggesting that it is also not a duplicate of a population of these species. If RAPDs can clearly differentiate populations within highly heterogeneous tetraploids like S. sucrense, they should be generally useful for determining germplasm organization within potato species. 相似文献
313.
Baxi MK Baxi S Clavijo A Burton KM Deregt D 《Veterinary journal (London, England : 1997)》2006,172(3):473-481
Foot-and-mouth disease virus (FMDV) is the most economically important veterinary pathogen because of its highly infectious nature and the devastating effects the virus has on the livestock industry. Rapid diagnostic methods are needed for detection and typing of FMDV serotypes and differentiation from other viruses causing vesicular diseases. We developed a microarray-based test that uses a FMD DNA chip containing 155 oligonucleotide probes, 35-45 base pair (bp) long, virus-common and serotype-specific, designed from the VP3-VP1-2A region of the genome. A set of two forward primers and one reverse primer were also designed to allow amplification of approximately 1100 bp of target sequences from this region. The amplified target was labelled with Alexa-Fluor 546 dye and applied to the FMD DNA chip. A total of 23 different FMDV strains representing all seven serotypes were detected and typed by the FMD DNA chip. Microarray technology offers a unique capability to identify multiple pathogens in a single chip. 相似文献
314.
Effect of two temperatures on yield and increase in cranial skeletal abnormalities during early development of palm ruff,Seriolella violacea (Guichenot 1848) 下载免费PDF全文
Wilfrido Argüello‐Guevara Milton Bohórquez‐Cruz Alfonso Silva 《Aquaculture Research》2017,48(1):298-310
The present study evaluates the effect of two temperatures, 14°C (T14) and 18°C (T18), on yield and the presence of cranial abnormalities during early development in north palm ruff (Seriolella violacea). Different time indices – days post‐hatching (DPH), degree‐days (D°) and effective degree‐days (D°eff) – were used to analyse growth during cultivation. Several ontogenetic events were achieved in less time during cultivation at 18°C. Additionally, a larger total length and final weight, as well as a higher survival rate, were achieved after 80 days of culture at higher temperatures (T18 = 55.5 ± 1.5 mm; 2.87 ± 0.21 g; 1.80 ± 0.18% and T14 = 24.3 ± 2.2 mm; 0.26 ± 0.08 g; 1.33 ± 0.12%). D° and D°eff were valid as independent temperature indices for predicting the growth response of S. violacea against thermal variations. The frequencies of cranial skeletal abnormalities (mouth and opercular complex) were evaluated in the pre‐flexion, flexion, post‐flexion and juvenile stages. However, the frequency of cranial skeletal abnormalities at the end of this study was not significantly influenced (P > 0.05) by temperature, and values below 21% were recorded in both treatments. These results can be of practical use for optimizing culture conditions to maximize the yield and quality of S. violacea juveniles. 相似文献
315.
Francisco Encina‐Montoya Rolando Vega‐Aguayo Alfonso Mardones‐Lazcano Teresa Rueda Alfredo Tello 《Aquaculture Research》2011,42(6):835-843
Galaxias maculatus is an osmeriform native fish of the Southern Hemisphere, in which the crystalline larvae is considered as a luxury delicacy, for this reason, it has been commercially exploited in Chile, Argentina and New Zealand. However, the fisheries have been rapidly decreasing due to the overexploitation and the predation of introduced species. Because of these events, there is a need to determine a carrying capacity for an intensive fish culture. In order to optimize stocking densities for fish culture, this paper proposes objectives to determine oxygen consumption (OC) rates, dissolved oxygen concentrations that produce signs of hypoxia and the average time elapsed between food intake and peak OC in G. maculatus. In the oxygen experiments under routine metabolism conditions, we found that G. maculatus adults and whitebait showed signs of asphyxia at dissolved oxygen concentrations between 1.3 and 2.2 mg L?1 and that adults tolerated dissolved oxygen levels as low as 1.3 mg L?1. The results showed that G. maculatus individuals with an average weight of 0.04 g consumed 0.048 mg O2 h?1, whereas individuals with an average weight of 1.4 g consumed 0.345 mg O2 h?1. Galaxias maculatus increased the OC rate by 31%, from 0.39 to 0.51 mg O2 h?1 g?1, occurring 14 min after food intake. The carrying capacities for industrial cultures of G. maculatus, were estimated using an allometric equation (OC=0.2363 ×W 0.612 ), a water flow rate of 1 m3 h?1 and an input oxygen concentration of 10 mg L?1 at 12 °C. The density culture of whitebait (4 g) can be allowed to reach 8–11 kg m?3; therefore, these stocking densities reduce the risk of hypoxia and mortality, ensuring the appropriate growth and feed conversion rates. 相似文献