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101.
Achilli A Rengo C Battaglia V Pala M Olivieri A Fornarino S Magri C Scozzari R Babudri N Santachiara-Benerecetti AS Bandelt HJ Semino O Torroni A 《American journal of human genetics》2005,76(5):883-886
The sequencing of entire human mitochondrial DNAs belonging to haplogroup U reveals that this clade arose shortly after the "out of Africa" exit and rapidly radiated into numerous regionally distinct subclades. Intriguingly, the Saami of Scandinavia and the Berbers of North Africa were found to share an extremely young branch, aged merely approximately 9,000 years. This unexpected finding not only confirms that the Franco-Cantabrian refuge area of southwestern Europe was the source of late-glacial expansions of hunter-gatherers that repopulated northern Europe after the Last Glacial Maximum but also reveals a direct maternal link between those European hunter-gatherer populations and the Berbers. 相似文献
102.
Carnevale S Velásquez JN Portillo HD Labbé JH Cabrera MG Ferella M Andersson B Guarnera EA Angel SO 《Experimental parasitology》2004,108(3-4):81-88
We cloned and characterized a Plasmodium vivax repeat element of 7872bp named PvRE7.8. Several internal tandem repeats were found along the sequence. The repetitive nature of the PvRE7.8 element was confirmed by hybridization of a P. vivax YAC library. Based on the data bank analysis and the presence of two contiguous putative genes that may encode proteins related to DNA metabolism, PvRE7.8 could be considered an inactivated transposon-LINE element. By using Pv79 as probe or primers derived from Pv79-flanking sequences, P. vivax DNA Could be detected from whole blood and mosquito samples. We consider that the repeat element described here has potential for P. vivax malaria diagnosis and for epidemiological analysis of P. vivax transmission areas. 相似文献
103.
Takeda AA dos Santos JI Marcussi S Silveira LB Soares AM Fontes MR 《Biochimica et biophysica acta》2004,1699(1-2):281-284
An acidic phospholipase A(2) (PLA(2)) isolated from Bothrops jararacussu snake venom was crystallized with two inhibitors: alpha-tocopherol (vitamin E) and p-bromophenacyl bromide (BPB). The crystals diffracted at 1.45- and 1.85-A resolution, respectively, for the complexes with alpha-tocopherol and p-bromophenacyl bromide. The crystals are not isomorphous with those of the native protein, suggesting the inhibitors binding was successful and changes in the quaternary structure may have occurred. 相似文献
104.
Extracellular calcium acts as a "third messenger" to regulate enzyme and alkaline secretion 总被引:1,自引:0,他引:1
Caroppo R Gerbino A Fistetto G Colella M Debellis L Hofer AM Curci S 《The Journal of cell biology》2004,166(1):111-119
It is generally assumed that the functional consequences of stimulation with Ca2+ -mobilizing agonists are derived exclusively from the second messenger action of intracellular Ca2+, acting on targets inside the cells. However, during Ca2+ signaling events, Ca2+ moves in and out of the cell, causing changes not only in intracellular Ca2+, but also in local extracellular Ca2+. The fact that numerous cell types possess an extracellular Ca2+ "sensor" raises the question of whether these dynamic changes in external [Ca2+] may serve some sort of messenger function. We found that in intact gastric mucosa, the changes in extracellular [Ca2+] secondary to carbachol-induced increases in intracellular [Ca2+] were sufficient and necessary to elicit alkaline secretion and pepsinogen secretion, independent of intracellular [Ca2+] changes. These findings suggest that extracellular Ca2+ can act as a "third messenger" via Ca2+ sensor(s) to regulate specific subsets of tissue function previously assumed to be under the direct control of intracellular Ca2+. 相似文献
105.
106.
Josy Campanhã Vicentini-Oliveira Silvana de Cássia Paulan Rosana Rossi-Ferreira Cáris Maroni Nunes 《Experimental parasitology》2010,126(4):621-625
Cysticercosis is a major cause of economic loss in bovine production due to meat condemnation. Chemotherapy is being used in Brazilian cattle and a diagnostic test to improve the treatment program is desired. We produced monoclonal antibodies against crude (TAEB) and cyst fluid (TAEF) Taenia saginata metacestode antigens using immunized BALB/c mice. After cell fusion, 10 TAEB and nine TAEF hybrids were selected and cloned resulting in 18 IgG1 and 32 IgM TAEB clones, and 9 IgG1 and 9 IgM TAEF clones. Ascites was produced and Western blot testing was performed resulting in reactivity to protein fractions of low molecular weight (<18 kDa), 43, 55, 66 and 100 kDa. The indirect immunofluorescence test, with one monoclonal antibody against crude and one against cyst fluid antigens, recognized antigenic fractions of both the scolex and the bladder wall of metacestodes from naturally infected bovine. 相似文献
107.
Silvana Condemi 《Human Evolution》2006,21(3-4):251-259
Today, a number of European fossils are known which can be dated between 500,000 and 900,000 years ago. These remains provide
evidence of an early human settlement of Europe, which apparently predates the emergence of Neanderthals. However, the taxonomic
attribution of these fossils and their phylogenetic relationship to each other and to Neanderthals remains unclear. Evidence
for a direct phylogenetic relationship with Neanderthals or a discontinuity is not yet conclusive. The task is complicated
by the fact that the emergence of the Neanderthal population was not abrupt, but progressive. It is probable that the peopling
of Europe during the entire Pleistocene was unique and presented from its very origins an “endemic” (a cul-de-sac) character,
which may explain that the first traces of fossils in Europe illustrate particularities in comparison those from Africa and
from Asia. Further paleontological discoveries will be needed to redefine the status of these features and to improve our
understanding of human evolution in Europe. 相似文献
108.
109.
Over the last decades, cholinesterase (ChE) biosensors have emerged as an ultra sensitive and rapid technique for toxicity analysis in environmental monitoring, food and quality control. These systems have the potential to complement or replace the classical analytical methods by simplifying or eliminating sample preparation protocols and making field testing easier and faster with significant decrease in costs per analysis. Over the years, engineering of more sensitive ChE enzymes, development of more reliable immobilization protocols and progress in the area of microelectronics could allow ChE biosensors to be competitive for field analysis and extend their applications to multianalyte screening, development of small, portable instrumentations for rapid toxicity testing, and detectors in chromatographic systems. In this paper, we will review the research efforts over the last 20 years in fabricating AChE biosensors and the recent trends and challenges encounter once the sensor is used outside research laboratory for in situ real sample applications. The review will discuss the generations of cholinesterase sensors with their advantages and limitations, the existing electrode configurations and fabrication techniques and their applications for toxicity monitoring. We will focus on low-cost electrochemical sensors and the approaches used for enzyme immobilization. Recent works for achieving high sensitivity and selectivity are also discussed. 相似文献
110.
Ivan Norscia Valentina Carrai Silvana M. Borgognini-Tarli 《International journal of primatology》2006,27(4):1001-1022
According to optimal foraging theory, herbivores can base food choice mainly on the quality or the quantity of food, or both. Among herbivorous primates, folivorous lemurs living in the highly seasonal environment of Madagascar have to cope with the shortage of high-quality food during the dry season, at least in deciduous forests. We studied (Verreaux's sifaka) in Kirindy, western Madagascar, to understand the influence of dry season and food quality and quantity on behavioral patterns and feeding strategy (qualitative vs. quantitative dietary choice) of a folivorous lemur in a deciduous forest. We followed 7 groups (4 groups/period; 3 individuals/group/month) during 4 periods of the year (wet season: February–March; early/middle/late dry season: May–June; July–September; October–November). We collected samples of plants eaten and examined behavioral and feeding patterns, considering food quality (macronutrients, proteins/fibers ratio, and tannins) and abundance. We found 1) a significant reduction of home range, core area, and daily path length from the wet to the dry season, possibly related to dietary change and 2) a daily period of inactivity in the dry season for energy conservation. Regarding the feeding strategy, Kirindy sifakas showed 1) high variation and selection in choosing food items and 2) a dietary choice based mainly on quality: Kirindy sifakas fed on plant species/families independently from their abundance and tannins represented a feeding deterrent during the dry season. Overall, behavioral and dietary adaptations allow Kirindy sifakas to overcome the shortage of high-quality food in the lean period. 相似文献