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41.
应用RAPD方法对近交系小鼠进行遗传检测的研究 总被引:10,自引:1,他引:10
目的 为实验室日常检测近交系小鼠的遗传背景提供一种分子生物学方法。方法 用 6条随机引物对 6个品系近交系小鼠基因组DNA进行PCR扩增。结果 6条随机引物中p2、p3、p5和p6四引物扩增的条带差异较为明显。结论 RAPD方法是一种有效的近交系小鼠遗传检测手段 相似文献
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Microbial fermentative preparation of L-[15N2]lysine and its tracer: application to serum amino acid kinetic studies 总被引:1,自引:0,他引:1
C S Irving C L Cooney L T Brown D Gold J Gordon P D Klein 《Analytical biochemistry》1983,131(1):93-98
The microorganism Brevibacterium flavum 21129 has been used to produce multigram batches of L-[15N2]lysine of high purity and isotopic enrichment by supplementation of the growth medium with (15NH4)2SO4 of 98.0 atom% excess. The doubly 15N-labeled lysine can be detected at dilutions 10 times greater than singly labeled lysine when isotope dilution curves are analyzed by gas chromatography-mass spectrometry. This enhanced sensitivity permits kinetic measurements of plasma free-lysine isotope content over a 300-fold dilution during 6 h following a single oral bolus of 5 mg/kg body wt. This inexpensive preparation method lends itself to the production of highly useful biochemical compounds for kinetic studies of human nutrition. 相似文献
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The rubber hand illusion (RHI) is a popular experimental paradigm. Participants view touch on an artificial rubber hand while the participants'' own hidden hand is touched. If the viewed and felt touches are given at the same time then this is sufficient to induce the compelling experience that the rubber hand is one''s own hand. The RHI can be used to investigate exactly how the brain constructs distinct body representations for one''s own body. Such representations are crucial for successful interactions with the external world. To obtain a subjective measure of the RHI, researchers typically ask participants to rate statements such as "I felt as if the rubber hand were my hand". Here we demonstrate how the crossmodal congruency task can be used to obtain an objective behavioral measure within this paradigm.The variant of the crossmodal congruency task we employ involves the presentation of tactile targets and visual distractors. Targets and distractors are spatially congruent (i.e. same finger) on some trials and incongruent (i.e. different finger) on others. The difference in performance between incongruent and congruent trials - the crossmodal congruency effect (CCE) - indexes multisensory interactions. Importantly, the CCE is modulated both by viewing a hand as well as the synchrony of viewed and felt touch which are both crucial factors for the RHI.The use of the crossmodal congruency task within the RHI paradigm has several advantages. It is a simple behavioral measure which can be repeated many times and which can be obtained during the illusion while participants view the artificial hand. Furthermore, this measure is not susceptible to observer and experimenter biases. The combination of the RHI paradigm with the crossmodal congruency task allows in particular for the investigation of multisensory processes which are critical for modulations of body representations as in the RHI. 相似文献
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P. Sodhani S. Gupta J. K. Sharma A. Parashari K. Halder V. Singh A. Sehgal 《Cytopathology》2006,17(6):348-352
OBJECTIVE: To determine test characteristics - sensitivity, specificity, positive and negative predictive values - of different screening modalities to detect cervical precancerous and cancerous lesions in order to devise an effective alternative strategy for cervical cancer screening in resource-poor settings. METHODS: A total of 472 women presenting with nonspecific gynecologic symptoms were screened by cytology, visual inspection with acetic acid application (VIA), VIA with magnification (VIAM) and human papillomavirus (HPV)-DNA testing. Colposcopic examination was performed in all and on-site biopsy was taken if any grade I and above lesion was detected on colposcopy (230). On histopathological examination, 105 showed cervical intraepithelial neoplasia II and above lesions. Sensitivity, specificity and predictive values for each test were calculated taking colposcopy and or directed biopsy as the gold standard. Comparisons were made with cytology in order to assess the feasibility of alternative strategies in resource-poor settings. RESULTS: VIA was less sensitive (86.7% versus 91.4%) but more specific (90.7% versus 86.6%) than cytology at low grade squamous intraepithelial lesion (LSIL) threshold but the difference was not statistically significant (P > 0.01). HPV testing improved the sensitivity over cytology (97.1% versus 91.4%) but there was a nonsignificant loss of specificity (84.2% versus 86.6%). Results of VIAM were more or less similar to VIA. CONCLUSION: VIA can be used as a mass screening tool for cervical cancer in resource-poor settings. 相似文献
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This paper investigates the causal relationships between per capita CO2 emissions, gross domestic product (GDP), renewable and non-renewable energy consumption, and international trade for a panel of 25 OECD countries over the period 1980–2010. Short-run Granger causality tests show the existence of bidirectional causality between: renewable energy consumption and imports, renewable and non-renewable energy consumption, non-renewable energy and trade (exports or imports); and unidirectional causality running from: exports to renewable energy, trade to CO2 emissions, output to renewable energy. There are also long-run bidirectional causalities between all our considered variables. Our long-run fully modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DOLS) estimates show that the inverted U-shaped environmental Kuznets curve (EKC) hypothesis is verified for this sample of OECD countries. They also show that increasing non-renewable energy increases CO2 emissions. Interestingly, increasing trade or renewable energy reduces CO2 emissions. According to these results, more trade and more use of renewable energy are efficient strategies to combat global warming in these countries. 相似文献
49.
Norma Julio Ana Sobral Juan Rondan Dueas Julio Di Rienzo Daniel Renison Isabell Hensen 《Biochemical Systematics and Ecology》2008,36(5-6):329-335
Two Polylepis australis BITT. populations differing in size were examined with the aim of determining future sampling strategies; assessing levels of genetic diversity and checking whether trees of different ages might vary in their genetic structure due to the effects of fragmentation. RADP and ISSR gave similar values of diversity. A re-sampling technique showed that for P. australis, 10 trees and 20 markers were enough to produce an unbiased estimator of heterozygosity. AMOVA suggested differences in allele frequencies between young and old trees in the small population (p = 0.052), but not in a large population (p = 0.864); suggesting that gene flow between the areas diminished in relatively recent times. This assumption is supported by the fact that allele frequencies among both woodlands were significantly different between the young (p < 0.0001), but not the older trees (p = 0.87). 相似文献
50.
Analysis of the composition of bacterial communities in oil reservoirs from a southern offshore Brazilian basin 总被引:2,自引:0,他引:2
Sette LD Simioni KC Vasconcellos SP Dussan LJ Neto EV Oliveira VM 《Antonie van Leeuwenhoek》2007,91(3):253-266
The aim of this study was to characterize and compare the bacterial community structure of two distinct oil samples from a
petroleum field in Brazil by using both molecular, based on the construction of 16S rRNA gene libraries, and cultivation methods.
Statistical comparisons of libraries based on Amplified Ribosomal DNA Restriction Analysis (ARDRA) data revealed no significant
differences between the communities recovered in the non-biodegraded (NBD) and highly biodegraded oils (HBD). BlastN analysis
of the 16S rRNA gene sequences representative of distinct ribotypes from both oils showed the presence of nine different bacterial
genera in these samples, encompassing members of the genera Arcobacter, Halanaerobium, Marinobacter, Propionibacterium, Streptomyces, Leuconostoc, Acinetobacter, Bacillus and Streptococcus. Enrichments obtained using oil as inoculum and sole carbon source yielded bacterial isolates showing high 16S rRNA gene
sequence similarity with Achromobacter xylosoxidans, Bacillus subtilis, Brevibacillus sp., Dietzia sp. and Methylobacterium sp. Comparison between the data obtained using cultivation-independent and enrichment cultures suggests that different selection
of community members may occur when using distinct approaches. All the organisms found, except for Leuconostoc sp. and Streptococus sp., have been previously reported in the literature as hydrocarbon degraders and/or associated to oil field environments. 相似文献