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81.
ERRATUM: Macho GA and Spears IR. 1999. Effects of Loading on the Biomechanical Behavior of Molars of Homo, Pan, and Pongo. Am J Phys Anthropol 109:211–227. The correct title of the article is given above. The word “biochemical” should be read as “biomechanical.”  相似文献   
82.
本文概述了缟蝇科昆虫的生活史、食性、访花习性、栖居环境等生物学特性,并对缟蝇科属、种的地理分布进行了分析。缟蝇科在世界动物地理区的分布统计结果表明,同脉缟蝇亚科为亚世界性分布,其属级阶元在东洋界丰富度最高,其次为澳洲界;其种级阶元在东洋界最为丰富,其次为澳洲界。缟蝇亚科为世界性分布,其属级阶元在新热带界丰富度最高,并且高度特化,其次是东洋界和澳洲界;其种级阶元在新热带界最为丰富,其次为古北界和澳洲界。缟蝇科在中国动物地理区和亚区的分布统计结果显示,其属、种级阶元在华南区最为丰富;同脉缟蝇亚科的种级阶元以海南岛亚区最为丰富,其次为台湾亚区;缟蝇亚科的种级阶元在台湾亚区最为丰富,西部山地高原亚区次之。  相似文献   
83.
肿瘤干细胞是肿瘤中具有自我更新能力和分化潜能,能产生异质性细胞的细胞。我们简要阐述了肿瘤干细胞存在的证据、分离技术及来源,并对以肿瘤干细胞为靶标的肿瘤治疗途径、临床应用前景和问题进行了综述。  相似文献   
84.
85.
Dps proteins are found almost ubiquitously in bacterial genomes and there is now an appreciation of their multifaceted roles in various stress responses. Previous studies have shown that this family of proteins assemble into dodecamers and their quaternary structure is entirely critical to their function. Moreover, the numbers of dps genes per bacterial genome is variable; even amongst closely related species - however, for many genera this enigma is yet to be satisfactorily explained. We reconstruct the most probable evolutionary history of Dps in Streptomyces genomes. Typically, these bacteria encode for more than one Dps protein. We offer the explanation that variation in the number of dps per genome among closely related Streptomyces can be explained by gene duplication or lateral acquisition, and the former preceded a subsequent shift in expression patterns for one of the resultant paralogs. We show that the genome of S. coelicolor encodes for three Dps proteins including a tailless Dps. Our in vivo observations show that the tailless protein, unlike the other two Dps in S. coelicolor, does not readily oligomerise. Phylogenetic and bioinformatic analyses combined with expression studies indicate that in several Streptomyces species at least one Dps is significantly over-expressed during osmotic shock, but the identity of the ortholog varies. In silico analysis of dps promoter regions coupled with gene expression studies of duplicated dps genes shows that paralogous gene pairs are expressed differentially and this correlates with the presence of a sigB promoter. Lastly, we identify a rare novel clade of Dps and show that a representative of these proteins in S. coelicolor possesses a dodecameric quaternary structure of high stability.  相似文献   
86.
一株石油降解菌培养基的优化   总被引:2,自引:0,他引:2  
目的:有效降低石油降解菌株CT-6在工业生产中的培养成本,提高培养速度。方法:利用Minitab软件,采用中心组合设计、响应面分析,以葡萄糖、蔗糖、可溶性淀粉为碳源,以硝酸铵、尿素、氯化铵为氮源,对高效降解石油菌株CT-6的培养基进行了优化。结果:当碳源葡萄糖为5.6818g/L、氮源氯化铵为3.8030g/L时,菌株CT-6培养17h,OD600达到0.615。结论:优化前后,菌体CT-6的OD600分别为0.289和0.615,提高了112.8%,说明该培养基更有利于菌株CT-6的生长。  相似文献   
87.

Background  

Genome and metagenome studies have identified thousands of protein families whose functions are poorly understood and for which techniques for functional characterization provide only partial information. For such proteins, the genome context can give further information about their functional context.  相似文献   
88.
The protein α-synuclein has a central role in Parkinson disease, but the mechanism by which it contributes to neural degeneration remains unknown. We now show that the expression of α-synuclein in mammalian cells, including neurons in vitro and in vivo, causes the fragmentation of mitochondria. The effect is specific for synuclein, with more fragmentation by α- than β- or γ-isoforms, and it is not accompanied by changes in the morphology of other organelles or in mitochondrial membrane potential. However, mitochondrial fragmentation is eventually followed by a decline in respiration and neuronal death. The fragmentation does not require the mitochondrial fission protein Drp1 and involves a direct interaction of synuclein with mitochondrial membranes. In vitro, synuclein fragments artificial membranes containing the mitochondrial lipid cardiolipin, and this effect is specific for the small oligomeric forms of synuclein. α-Synuclein thus exerts a primary and direct effect on the morphology of an organelle long implicated in the pathogenesis of Parkinson disease.  相似文献   
89.
The interstitial cells of Cajal (ICC) have been reported to regulate gastrointestinal motility. We investigated the distribution and the morphological and morphometric characteristics of the immunohistochemical reaction against c-kit in the forestomachs of fetal, newborn and adult cows. The anti-c-kit reaction revealed different populations of ICC among age groups and organs. ICC were more numerous and smaller in fetuses. Larger ICC were identified in newborns, except for those in the rumen. During the earliest stages of development, ICC were abundant in the inner layer of the muscularis and were consistently associated with this layer. In all samples, ICC were found in the outer layer of the tunica muscularis. ICC were found between the two muscle layers in the omasum at all ages; however, they were identified only in the rumen of the adult. Our study demonstrated that ICC are present in the forestomach of bovines.  相似文献   
90.
目的:分析新疆地区近20年来胃癌流行病学特征,探讨其变化规律及发展趋势。方法:回顾性分析和比较1991年、2001年、2011年经新疆维吾自治区人民医院胃镜及病理学诊断确诊为胃癌的病例的一般资料、病理学及内镜下特点,包括性别、年龄、病理类型、发病部位。结果:1991年组:胃癌检出率为2.48%,中位年龄为54岁,男女之比为3-3:1.0,发病部位以胃窦部癌为主,占39.1%;2001年组:检出率为2.39%,中位年龄为61岁,男女之比为3.0:1.0,发病部位以胃体部癌为主,占42.1%;2011年组:检出率为1.48%,中位年龄为63岁,男女之比为3.9:1.0,发病部位以贵门胃底部为主,占34.8%。三组病理学类型均以腺癌为主,检出率有逐年升高趋势,但差异无统计学意义(P〉0.05)。结论:(1)近20年来胃癌发病部位有上移现象,且胃癌检发病率有下降趋势;(2)男性胃癌患者发病率明显高于女性,且近20年来胃癌患者男女比例无明显改变;(3)近20年来胃癌发病中位年龄逐渐增高,且随着年龄的增长发病率逐渐升高,以中老年发病率最高;(4)癌患者病理类型仍以腺癌为主,且近20年来腺癌所占比例无明显变化.  相似文献   
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