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71.
Serological data identify a single major histocompatibility complex (MHC) class I locus in cattle. Molecular data, however, demonstrate the presence of at least two cattle MHC (BoLA) class I loci. To investigate the number of transcribed BoLA class I genes, we amplified cattle cDNA by using a single MHC class I-specific primer that hybridized to a conserved region of exon 4 and a non-specific 3 primer. Six BoLA class I cDNAs have been cloned and sequenced from a Bos taurus bull heterozygous for BoLA class I serological antigens, demonstrating the presence of a minimum of three loci. Sequence comparisons suggested that one of these cDNAs may be an unexpressed allele or the product of a nonclassical locus.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers U01186 and U01187.  相似文献   
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The fate of stem cells is intricately regulated by numerous extrinsic and intrinsic factors that promote maintenance or differentiation. The RNA-binding translational repressor Pumilio (Pum) in conjunction with Nanos (Nos) is required for self-renewal, whereas Bam (bag-of-marbles) and Bgcn (benign gonial cell neoplasm) promote differentiation of germ line stem cells in the Drosophila ovary. Genetic analysis suggests that Bam and Bgcn antagonize Pum/Nos function to promote differentiation; however, the molecular basis of this epistatic relationship is currently unknown. Here, we show that Bam and Bgcn inhibit Pum function through direct binding. We identified a ternary complex involving Bam, Bgcn, and Pum in which Bam, but not Bgcn, directly interacts with Pum, and this interaction is greatly increased by the presence of Bgcn. In a heterologous reporter assay to monitor Pum activity, Bam, but not Bgcn, inhibits Pum activity. Notably, the N-terminal region of Pum, which lacks the C-terminal RNA-binding Puf domain, mediates both the ternary protein interaction and the Bam inhibition of Pum function. These studies suggest that, in cystoblasts, Bam and Bgcn may directly inhibit Pum/Nos activity to promote differentiation of germ line stem cells.  相似文献   
74.
Thoracic ultrasound (TUS) is an easy-to-use imaging modality that aids physicians in the differential diagnosis of respiratory diseases. However, no data exist on the TUS findings of acute eosinophilic pneumonia (AEP) or their clinical utility in patients with AEP. Thus, we performed an observational study on TUS findings and their clinical utility for follow-up in patients with AEP. We prospectively screened patients who visited the emergency department for acute respiratory symptoms at the Armed Forces Capital Hospital in South Korea between February 2014 and July 2014. Of them, patients suspected to have AEP underwent an etiological investigation, including flexible bronchoscopy with bronchoalveolar lavage and TUS, and we evaluated TUS findings and serial changes on TUS during the treatment course compared with those from chest radiographs. In total, 22 patients with AEP were identified. The TUS examinations reveled that all patients exhibited multiple diffuse bilateral B-lines and lung sliding, with (n = 5) or without pleural effusion, which was consistent with alveolar-interstitial syndrome. B-line numbers fell during the course of treatment, as the lines became thinner and fainter. A-lines were evident in 19 patients on day 7 of hospitalization, when B-lines had disappeared in 13 patients, and all pleural effusion had resolved. All patients exhibited complete ultrasonic resolution by day 14, along with clinicoradiological improvement. Chest radiographs of five patients taken on day 7 seemed to show complete resolution, but several abnormal B-lines were evident on TUS performed the same day. As a result, our data show common TUS findings of AEP and suggest that AEP may be included as a differential diagnosis when multiple diffuse bilateral B-lines with preserved lung sliding are identified on a TUS examination in patients with acute symptoms, and that TUS is a useful modality for evaluating the treatment response in patients with AEP.  相似文献   
75.
Cobalt-rich crusts are important metallic mineral resources with great economic potential, usually distributed on seamounts located in the Pacific Ocean. Microorganisms are believed to play a role in the formation of crusts as well as in metal cycling. To explore the microbial diversity related to cobalt-rich crusts, 16S ribosomal RNA gene clone libraries were constructed from three consecutive sediment layers. In total, 417 bacterial clones were obtained from three bacterial clone libraries, representing 17 distinct phylogenetic groups. Proteobacteria dominated in the bacterial communities, followed by Acidobacteria and Planctomycetes. Compared with high bacterial diversity, archaea showed a remarkably low diversity, with all 137 clones belonging to marine archaeal group I except one novel euryarchaeotal clone. The microbial communities were potentially involved in sulfur, nitrogen and metal cycling in the area of cobalt-rich crusts. Sulfur oxidation and metal oxidation were potentially major sources of energy for this ecosystem. This is the first reported investigation of microbial diversity in sediments associated with cobalt-rich crusts, and it casts fresh light on the microbial ecology of these important ecosystems.  相似文献   
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Globalization has changed the habitats of various species, resulting in harmful pest invasion. Among these pests, Metcalfa pruinosa has caused worldwide economic and hygienic damage in both urban and agricultural/forested areas. It has been reported that prediction of pest distribution is key to the management of pest prevention. Hence, this study aimed to predict the potential geographic distribution of M. pruinosa under the current climate and under a climate change scenario. CLIMEX, modeling software that analyzes the habitat suitability of a target species based on comprehensive climatic and physiological data, was used mainly to establish a map of predictive distribution of M. pruinosa at present and in the future. Based on our simulations, we predict that M. pruinosa will tend to extend its distribution northward in North America and Europe. We conclude that climate change could result in M. pruinosa invasion in a northward direction, suggesting the need for a thorough system of control and prevention.  相似文献   
79.
Several prodrug approaches were taken to mask amino groups in two potent and selective neuronal nitric oxide synthase (nNOS) inhibitors containing either a primary or secondary amino group to lower the charge and improve blood–brain barrier (BBB) penetration. The primary amine was masked as an azide and the secondary amine as an amide or carbamate. The azide was not reduced to the amine under a variety of in vitro and ex vivo conditions. Despite the decrease in charge of the amino group as an amide and as carbamates, BBB penetration did not increase. It appears that the uses of azides as prodrugs for primary amines or amides and carbamates as prodrugs for secondary amines are not universally effective for CNS applications.  相似文献   
80.
岩亮洞是广西扶绥地区最近新发现的早更新世巨猿化石点,经过初步发掘,采集到了丰富的巨猿材料及大量伴生的哺乳动物化石。引人注目的是其中犀类化石居多,包括146颗完整的牙齿及十多件头后骨骼化石,从形态特征判断,这些犀类化石应属于独角犀的一新种Rhinoceros fusuiensis。岩亮洞巨猿动物群中的独角犀以种群丰度最大而不同于其他已知东亚地区的巨猿动物群中的独角犀类材料。本文从犀类牙齿的主尖釉质层、齿质暴露程度、咀嚼面的磨蚀程度等方面对岩亮洞独角犀的年龄结构进行了研究。该死亡群中至少有4头幼年个体、5头青年个体、5头成年个体和1头老年个体。依据牙齿磨蚀程度和牙齿萌出顺序对年龄结构的分析及统计显示,其中青年个体和成年个体最多,幼年个体次之,老年个体最少,其死亡的原因不是通常意义上磨耗型死亡,突发性的灾害可能是造成这种死亡年龄分布的主要原因。  相似文献   
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