全文获取类型
收费全文 | 56篇 |
免费 | 9篇 |
出版年
2021年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1992年 | 1篇 |
1986年 | 1篇 |
1983年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 5篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有65条查询结果,搜索用时 15 毫秒
41.
42.
Indoleacetic acid in physiological concentrations was shown to enhance the synthesis of citiate by purified citrate condensing enzyme from castor beans and pig heart. Michaelis constants reveal that with indoleacetic acid in the reaction mixture a higher concentration of acetyl-CoA was necessary to give maximal velocity. V values with indoleacetic acid in the reaction (physiological concentrations) exceeded V without indoleacetic acid in reaction. Citric acid synthesized from 14C acetyl CoA was highly radioactive when indoleacetie acid was present in the reaction, indicating that indoleacetic acid did in fact enhance the synthesis. The data were discussed from the point of view that these studies may provide the basis for studies directed at ultimate understanding of the mechanism of action of indoleacetic acid. 相似文献
43.
Armen A. Galoyan Naser Khalaji Lilja E. Hambardzumyan Larisa P. Manukyan Irina B. Meliksetyan Vergine A. Chavushyan Vaghinak H. Sarkisian John S. Sarkissian 《Neurochemical research》2010,35(11):1747-1760
We tested the action of proline-rich peptide (PRP-1) and cobra venom Naja Naja Oxiana (NOX) on Deiters’ nucleus neurons at
3rd, 15th and 35th days after unilateral labyrinthectomy (UL). Early and late tetanic, post-tetanic potentiation and depression
of Deiters’neurons to bilateral high frequency stimulation of hypothalamic supraoptic and paraventricualar nuclei was studied.
The analysis of spike activity was carried out by mean of on-line selection and special program. The complex averaged peri-event
time and frequency histograms shows the increase of inhibitory and excitatory reactions of Deiters’ neurons at early stage
of vestibular compensation following PRP-1 and NOX injection, reaching the norm at the end of tests. In histochemical study
the changes in Ca2+-dependent acidic phosphatase (AP) activity in neurons was discovered. It was shown that in UL animals the total disappearance
or delay of decolorizing of Deiters’ neurons lead to neurodegenerative pattern as cellular “shade”. AP activity after UL and
PRP-1 injection exerts more effective recovery of neurons in comparison with events, observed after the administration of
NOX. The data of this study indicate that PRP-1 and NOX are protectors, which may successfully recover the disturbed vestibular
functions. 相似文献
44.
45.
Kinetics of utilization of acetyl coenzyme A by citrate synthase of a sea anemone, an osmoconformer, were compared with those of citrate synthases of various osmoregulators. The Kms of the latter enzymes were substantially increased by higher concentrations of salt and the enzyme exhibited hyperbolic substrate saturation curves. Citrate synthase from sea anemone, on the other hand, exhibited allosteric kinetics and minimal effects of salt on its Km. We suggest that the adaptive advantage of this enzymic property to a sedentary osmoconforming organism such as sea anemone is obvious since the osmoregulating creatures are apparently unable to maintain an appropriate low ionic environment in situ and thus probably the Km of their citrate synthases at a low level. 相似文献
46.
Ancient DNA analysis identifies marine mollusc shells as new metagenomic archives of the past
下载免费PDF全文
![点击此处可从《Molecular ecology resources》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Clio Der Sarkissian Vianney Pichereau Catherine Dupont Peter C. Ilsøe Mickael Perrigault Paul Butler Laurent Chauvaud Jón Eiríksson James Scourse Christine Paillard Ludovic Orlando 《Molecular ecology resources》2017,17(5):835-853
Marine mollusc shells enclose a wealth of information on coastal organisms and their environment. Their life history traits as well as (palaeo‐) environmental conditions, including temperature, food availability, salinity and pollution, can be traced through the analysis of their shell (micro‐) structure and biogeochemical composition. Adding to this list, the DNA entrapped in shell carbonate biominerals potentially offers a novel and complementary proxy both for reconstructing palaeoenvironments and tracking mollusc evolutionary trajectories. Here, we assess this potential by applying DNA extraction, high‐throughput shotgun DNA sequencing and metagenomic analyses to marine mollusc shells spanning the last ~7,000 years. We report successful DNA extraction from shells, including a variety of ancient specimens, and find that DNA recovery is highly dependent on their biomineral structure, carbonate layer preservation and disease state. We demonstrate positive taxonomic identification of mollusc species using a combination of mitochondrial DNA genomes, barcodes, genome‐scale data and metagenomic approaches. We also find shell biominerals to contain a diversity of microbial DNA from the marine environment. Finally, we reconstruct genomic sequences of organisms closely related to the Vibrio tapetis bacteria from Manila clam shells previously diagnosed with Brown Ring Disease. Our results reveal marine mollusc shells as novel genetic archives of the past, which opens new perspectives in ancient DNA research, with the potential to reconstruct the evolutionary history of molluscs, microbial communities and pathogens in the face of environmental changes. Other future applications include conservation of endangered mollusc species and aquaculture management. 相似文献
47.
Abrahamyan SS Meliksetyan IB Sulkhanyan RM Sarkissian JS Galoyan AA 《Neurochemical research》2001,26(11):1225-1230
Previously by immunohistochemical technique the distribution of immunophilin 1–15 fragment (IphF) isolated from bovine hypothalamus was examined in various tissues (heart, lung), including immune system organs (spleen and thymus) of intact rats. IphF-like immunoreactivity (IphF-LI) was revealed in several cell types: lymphocytes, monocytes, macrophages and mast cells. In the present study the immunohistochemical localization of IphF was examined in intact rat and frog brains. In rat brain several cell groups concentrated particularly in the supraoptic nucleus (SON) of hypothalamus, medulla oblongata (reticular formation, olives, hypoglossal and facial motor nuclei) and cerebellum (lateral cerebellar nucleus) demonstrated IphF-LI. In frog hypothalamus (SON) the same working dilution (1:5000) of IphF-antiserum revealed very strong immunoreactivity. In the paraventricular nucleus (PVN) IphF-LI varicosities were scattered around the immunonegative cells. The second cell groups showing IphF-LI in the frog brain were gliocytes (mainly the astrocytes). Besides, IphF distribution was investigated in rats subjected to hemisection of spinal cord (SC) with and without administration of proline-rich polypeptide (PRP). PRP was isolated from bovine neurohypophysis neurosecretory granules, produced by magnocellular nuclei of hypothalamus. Hemisection of SC led to changes of IphF distribution in the hypothalamus. In PRP treated animals IphF showed no immunoreactivity. PRP is suggested to act as a neurotransmitter and neuroregulator. 相似文献
48.
Pierre-Henri Fabre Julia T. Vilstrup Maanasa Raghavan Clio Der Sarkissian Eske Willerslev Emmanuel J. P. Douzery Ludovic Orlando 《Biology letters》2014,10(7)
The Capromyidae (hutias) are endemic rodents of the Caribbean and represent a model of dispersal for non-flying mammals in the Greater Antilles. This family has experienced severe extinctions during the Holocene and its phylogenetic affinities with respect to other caviomorph relatives are still debated as morphological and molecular data disagree. We used target enrichment and next-generation sequencing of mitochondrial and nuclear genes to infer the phylogenetic relationships of hutias, estimate their divergence ages, and understand their mode of dispersal in the Greater Antilles. We found that Capromyidae are nested within Echimyidae (spiny rats) and should be considered a subfamily thereof. We estimated that the split between hutias and Atlantic Forest spiny rats occurred 16.5 (14.8–18.2) million years ago (Ma), which is more recent than the GAARlandia land bridge hypothesis (34–35 Ma). This would suggest that during the Early Miocene, an echimyid-like ancestor colonized the Greater Antilles from an eastern South American source population via rafting. The basal divergence of the Hispaniolan Plagiodontia provides further support for a vicariant separation between Hispaniolan and western islands (Bahamas, Cuba, Jamaica) hutias. Recent divergences among these western hutias suggest Plio-Pleistocene dispersal waves associated with glacial cycles. 相似文献
49.
Haak W Balanovsky O Sanchez JJ Koshel S Zaporozhchenko V Adler CJ Der Sarkissian CS Brandt G Schwarz C Nicklisch N Dresely V Fritsch B Balanovska E Villems R Meller H Alt KW Cooper A;Members of the Genographic Consortium 《PLoS biology》2010,8(11):e1000536
In Europe, the Neolithic transition (8,000–4,000 b.c.) from hunting and gathering to agricultural communities was one of the most important demographic events since the initial peopling of Europe by anatomically modern humans in the Upper Paleolithic (40,000 b.c.). However, the nature and speed of this transition is a matter of continuing scientific debate in archaeology, anthropology, and human population genetics. To date, inferences about the genetic make up of past populations have mostly been drawn from studies of modern-day Eurasian populations, but increasingly ancient DNA studies offer a direct view of the genetic past. We genetically characterized a population of the earliest farming culture in Central Europe, the Linear Pottery Culture (LBK; 5,500–4,900 calibrated b.c.) and used comprehensive phylogeographic and population genetic analyses to locate its origins within the broader Eurasian region, and to trace potential dispersal routes into Europe. We cloned and sequenced the mitochondrial hypervariable segment I and designed two powerful SNP multiplex PCR systems to generate new mitochondrial and Y-chromosomal data from 21 individuals from a complete LBK graveyard at Derenburg Meerenstieg II in Germany. These results considerably extend the available genetic dataset for the LBK (n = 42) and permit the first detailed genetic analysis of the earliest Neolithic culture in Central Europe (5,500–4,900 calibrated b.c.). We characterized the Neolithic mitochondrial DNA sequence diversity and geographical affinities of the early farmers using a large database of extant Western Eurasian populations (n = 23,394) and a wide range of population genetic analyses including shared haplotype analyses, principal component analyses, multidimensional scaling, geographic mapping of genetic distances, and Bayesian Serial Simcoal analyses. The results reveal that the LBK population shared an affinity with the modern-day Near East and Anatolia, supporting a major genetic input from this area during the advent of farming in Europe. However, the LBK population also showed unique genetic features including a clearly distinct distribution of mitochondrial haplogroup frequencies, confirming that major demographic events continued to take place in Europe after the early Neolithic. 相似文献
50.
Proteins of hypocotyls of bean were studied by electrophoresis. Proteins were extracted from hypocotyl segments of various stages of development starting with the relatively undifferentiated hook regions and proceeding by 2 cm segments down the hypocotyl. The proteins were the soluble (pH 7.4), the basic nuclear (histones), acidic ribonuclear and acidic chromosomal. Soluble proteins reflected differentiation of the hypocotyl in that lower hypocotyl segments had more different protein types than did the hook region. Indoleacetic acid (IAA) at 10?6M when applied to the lower hypocotyl appeared to induce still more different proteins. However, at 10?3M, IAA appeared to induce molecular dedifferentiation in that hypocotyl protein patterns began to resemble those of the hook. Histones also reflected differentiation, the hook having more histone types than the lower hypocotyl. IAA had no effect on histones. The hook region had two types of acidic chromosomal proteins, the lower hypocotyl one. When lower hypocotyl segments were incubated in 10?3M IAA, the protein pattern resembled that of the hook in that the second protein normally present in the hook and not in the hypocotyl was in fact induced in the hypocotyl. The hook had two acidic ribonuclear proteins, the lower hypocotyl one. IAA did not affect this protein. These experiments suggest that IAA in some manner regulates molecular (protein) differentiation. It is further suggested that IAA accomplishes this control through the acidic nuclear proteins which are closely associated with genetic material and which reflect differentiation and are also affected by IAA. 相似文献