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1.
Reverse-phase high-performance liquid chromatography was utilized to separate efficiently and rapidly a standard mixture of various radiolabeled O-methylated mannitols and O-methylfucitol commonly encountered when vertebrate asparagine-linked oligosaccharides are subjected to permethylation, hydrolysis, and reduction with NaBH4. The following reduced, radioactive O-methylhexitols were resolved: 2,4-, 3,4-, and 3,6-di-O-methylmannitols; 3,4,6-tri-O-methylmannitol, 2,3,4-tri-O-methylfucitol, and 2,3,4,6-tetra-O-methylmannitol. To demonstrate the utility of this separation method in the analysis of metabolically radiolabeled asparagine-linked oligosaccharides, mouse lymphoma BW 5147 cells were metabolically radiolabeled with [2-3H]mannose and their glycopeptides prepared by Pronase digestion and fractionated by serial chromatography on immobilized lectins. Each fraction was subjected to methylation and hydrolysis, the released monosaccharides were reduced, and the radioactive O-methylhexitols were separated by reverse-phase HPLC. The relative amounts of the O-methylhexitols in each glycopeptide fraction analyzed were similar to those values determined by a combination of other separation systems.  相似文献   
2.
T-cell dysfunction and hyperimmunoglobulinemia E in paracoccidioidomycosis   总被引:1,自引:1,他引:0  
Various aspects of T and B cell mediated immunity were investigated in 20 well documented cases of active (10) or inactive (10) paracoccidioidomycosis (Pcm), as well as in 8 healthy individuals living in the endemic area of the disease. The results confirm previous reports that active Pcm produces diverse grades of depression of T cell mediated immunity. Such T cell dysfunction is not associated with a reduction in the number of peripheral E rosette-forming cells, and the immunodepression is reversed by chemotherapy. Sera from Pcm (active or inactive) patients have significantly increased levels of total IgE, but the actual proportion of IgE antibodies against P. brasiliensis was very low (0.4–0.6%). The highest levels of total IgE were found in active patients with disease-related immune depression, suggesting that T cell dysfunction might contribute to the excessive IgE production.  相似文献   
3.
Different values have resulted in conflicts between anglers and conservation lobbies in the management of trout in South Africa. Key to the conflict is the demarcation of boundaries to areas in which brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss currently occur, or are likely to establish following stocking for angling. To provide a longer-term perspective on these areas, we developed models to link salmonid biological thermal thresholds to elevation. These, when applied spatially using a digital elevation model with a probability of occurrence model, provided the basis for estimating potentially available thermal habitat for these two cold water species. Here, we acknowledge that other variables (stocking history; river connectivity) also play a role in understanding trout distributions. Using a simple scenario of an increase in mean daily water temperatures of 2 °C, we demonstrated that both brown and rainbow trout are likely to exhibit considerable range reductions in the future. Because it is possible that these range restrictions will result in an increasing desire to introduce trout into areas above their current distribution limits for the maintenance of angling opportunities, conservation managers should prioritise these areas, with management interventions seeking to understand what will help to limit introductions.  相似文献   
4.

Background

Genomic selection (GS) using estimated breeding values (GS-EBV) based on dense marker data is a promising approach for genetic improvement. A simulation study was undertaken to illustrate the opportunities offered by GS for designing breeding programs. It consisted of a selection program for a sex-limited trait in layer chickens, which was developed by deterministic predictions under different scenarios. Later, one of the possible schemes was implemented in a real population of layer chicken.

Methods

In the simulation, the aim was to double the response to selection per year by reducing the generation interval by 50 %, while maintaining the same rate of inbreeding per year. We found that GS with retraining could achieve the set objectives while requiring 75 % fewer reared birds and 82 % fewer phenotyped birds per year. A multi-trait GS scenario was subsequently implemented in a real population of brown egg laying hens. The population was split into two sub-lines, one was submitted to conventional phenotypic selection, and one was selected based on genomic prediction. At the end of the 3-year experiment, the two sub-lines were compared for multiple performance traits that are relevant for commercial egg production.

Results

Birds that were selected based on genomic prediction outperformed those that were submitted to conventional selection for most of the 16 traits that were included in the index used for selection. However, although the two programs were designed to achieve the same rate of inbreeding per year, the realized inbreeding per year assessed from pedigree was higher in the genomic selected line than in the conventionally selected line.

Conclusions

The results demonstrate that GS is a promising alternative to conventional breeding for genetic improvement of layer chickens.  相似文献   
5.
Nutrient enrichment threatens river ecosystem health in urban watersheds, but the influence of urbanization on spatial variation in nutrient concentrations and nutrient limitation of biofilm activity are infrequently measured simultaneously. In summer 2009, we used synoptic sampling to measure spatial patterns of nitrate (NO3 ), ammonium (NH4 +), and soluble reactive phosphorus (SRP) concentration, flux, and instantaneous yield throughout the Bronx River watershed within New York City and adjacent suburbs. We also quantified biofilm response to addition of NO3 , phosphate (PO4 3−), and NO3  + PO4 3− on organic and inorganic surfaces in the river mainstem and tributaries. Longitudinal variation in NO3 was low and related to impervious surface cover across sub-watersheds, but spatial variation in NH4 + and SRP was higher and unrelated to sub-watershed land-use. Biofilm respiration on organic surfaces was frequently limited by PO4 3− or NO3  + PO4 3−, while primary production on organic and inorganic surfaces was nutrient-limited at just one site. Infrequent NO3 limitation and low spatial variability of NO3 throughout the watershed suggested saturation of biological N demand. For P, both higher biological demand and point-sources contributed to greater spatial variability. Finally, a comparison of our data to synoptic studies of forested, temperate watersheds showed lower spatial variation of N and P in urban watersheds. Reduced spatial variation in nutrients as a result of biological saturation may represent an overlooked effect of urbanization on watershed ecology, and may influence urban stream biota and downstream environments.  相似文献   
6.
本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...  相似文献   
7.
肠道病毒71型作为引起儿童群体常见传染性手足口病(HFMD)的主要病原,具有导致少量感染个体出现脑炎等神经系统病变以及相关心肺功能衰竭的病理学特性.因此其预防性疫苗的研发具有重要的公共卫生意义.在前期工作的基础上,一种EV71灭活病毒疫苗(人二倍体细胞)在本研究中基于恒河猴婴猴模型进行了相应的免疫保护性分析.以160EU剂量对2~3月龄婴猴进行0,4周免疫后,动物在第4周接受了剂量为10。~CCID50的病毒经呼吸道的攻击.对病毒攻击后动物在14天内的临床症状、血液生物学、器官病原学分布以及病理学检测的动态观察表明,经疫苗免疫的动物未出现对照动物所具有的特征性临床表现,其血液生物学及病理学检测均无异常.同时,器官病原学分布亦呈阴性.结合动物中和抗体的明确增长及对照动物的综合表现分析,本文的工作证实了该EV71灭活病毒疫苗(人二倍体细胞)在恒河猴婴猴体内的免疫保护性.  相似文献   
8.
A literature review was performed on the laws passed, and adopted in accordance with international regulations, in Colombia and which currently benefit or affect the quality of life of the elderly. Public policies in Colombia are inclined towards the well-being of the elderly, but this documental analysis concludes that the elderly Colombian is unprotected and defenceless against the obstacles and difficult situations due to the biological, political, social, economic and environmental conditions. This makes them vulnerable as it is a scheme that only benefits in cases of poverty and by being a member of the General Social Security in Health system, with transfer of obligations to the family, society and likewise the elderly.  相似文献   
9.
娜琴  图力古尔 《菌物学报》2020,39(9):1783-1808
报道了小菇科小菇属真菌10个中国新记录种,香菌组:橙盖小菇Mycena aurantiidisca、黄白小菇Mycena flavoalba、粉黄小菇Mycena floridula;棘刺组:异刺小菇Mycena heteracantha;纤柄组:碱味小菇Mycena amygdalina;脆足组:粉被小菇Mycena zephirus;冬生组:绣线菊小菇Mycena speirea、冬生小菇Mycena hiemalis;小菇组:绒柄小菇Mycena flos-nivium,分别来自吉林等11个省份、自治区。提供了每个物种的形态描述和线条图,以及与相近种的讨论。共计90条自测及下载ITS序列,在采用贝叶斯法和最大似然法构建的小菇属系统发育树中,新记录种均得到分子数据支持。凭证标本存放于吉林农业大学菌物标本馆(HMJAU)。  相似文献   
10.
依据2003年到2005年松嫩平原西部地区珍稀鹤类巢址调查数据,利用三种不同类型的指数进行分析研究:(1)拓扑指数,Voronoi图面积;(2)统计指数,Morishita指数;(3)空间指数,分维数.结果表明珍稀鹤类巢址空间格局具有明显的空间聚类分布,这三个指数使我们对珍稀鹤类巢址的聚类现象有了定量的认识,加深对自然保护区资源保护的重要性.  相似文献   
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