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排序方式: 共有210条查询结果,搜索用时 15 毫秒
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Thirty-nine previously unpublished reports of the endangered black-footed ferret from Wyoming are listed with dates, locations, number of animals, sources, and comments. 相似文献
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To assess the potential hazard from radioactive wastes, a plant with known radiosensitivity, Tradescantia clone 02, was grown in radioactive soil obtained from uranium mill tailings. The levels of radiation on these tailings varied from 0.03mR/hr (background) to a maximum of 3.00 mR/hr. Tradescantia grown in soil with a radiation level greater than 0.10 mR/hr evidenced significantly reduced reproductive integrity and fecundity, as measured by the number of stunted hairs per stamen, pollen viability, and numbers of somatic mutations. Based on these data, the radioactivity from uranium mill tailings has the potential to alter normal plant succession due to its detrimental effect on any species that is relatively radiosensitive. 相似文献
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Margaret Campbell 《Annals of science》2013,70(6):639-655
It is argued that de Vries did not see Mendel's paper until 1900, and that, while his own theory of inheritance may have incorporated the notion of independent units, this pre-Mendelian formulation was not the same as Mendel's since it did not apply to paired hereditary units. Moreover, the way in which the term ‘segregation’ has been applied in the secondary literature has blurred the distinction between what is explained and the law which facilitates explanation. 相似文献
6.
M L Kashyap S G de Mendoza M Campbell C Y Chen R F Lutmer C J Glueck 《Experientia》1978,34(8):1044-1045
Marked urinary loss of lipoprotein lipase activator in experimental rat nephrotic syndrome may be partly responsible for its deficiency in plasma very low density lipoproteins. 相似文献
7.
van Kasteren SI Kramer HB Jensen HH Campbell SJ Kirkpatrick J Oldham NJ Anthony DC Davis BG 《Nature》2007,446(7139):1105-1109
One of the most important current scientific paradoxes is the economy with which nature uses genes. In all higher animals studied, we have found many fewer genes than we would have previously expected. The functional outputs of the eventual products of genes seem to be far more complex than the more restricted blueprint. In higher organisms, the functions of many proteins are modulated by post-translational modifications (PTMs). These alterations of amino-acid side chains lead to higher structural and functional protein diversity and are, therefore, a leading contender for an explanation for this seeming incongruity. Natural protein production methods typically produce PTM mixtures within which function is difficult to dissect or control. Until now it has not been possible to access pure mimics of complex PTMs. Here we report a chemical tagging approach that enables the attachment of multiple modifications to bacterially expressed (bare) protein scaffolds: this approach allows reconstitution of functionally effective mimics of higher organism PTMs. By attaching appropriate modifications at suitable distances in the widely-used LacZ reporter enzyme scaffold, we created protein probes that included sensitive systems for detection of mammalian brain inflammation and disease. Through target synthesis of the desired modification, chemistry provides a structural precision and an ability to retool with a chosen PTM in a manner not available to other approaches. In this way, combining chemical control of PTM with readily available protein scaffolds provides a systematic platform for creating probes of protein-PTM interactions. We therefore anticipate that this ability to build model systems will allow some of this gene product complexity to be dissected, with the aim of eventually being able to completely duplicate the patterns of a particular protein's PTMs from an in vivo assay into an in vitro system. 相似文献
8.
PTC124 targets genetic disorders caused by nonsense mutations 总被引:1,自引:0,他引:1
Welch EM Barton ER Zhuo J Tomizawa Y Friesen WJ Trifillis P Paushkin S Patel M Trotta CR Hwang S Wilde RG Karp G Takasugi J Chen G Jones S Ren H Moon YC Corson D Turpoff AA Campbell JA Conn MM Khan A Almstead NG Hedrick J Mollin A Risher N Weetall M Yeh S Branstrom AA Colacino JM Babiak J Ju WD Hirawat S Northcutt VJ Miller LL Spatrick P He F Kawana M Feng H Jacobson A Peltz SW Sweeney HL 《Nature》2007,447(7140):87-91
Nonsense mutations promote premature translational termination and cause anywhere from 5-70% of the individual cases of most inherited diseases. Studies on nonsense-mediated cystic fibrosis have indicated that boosting specific protein synthesis from <1% to as little as 5% of normal levels may greatly reduce the severity or eliminate the principal manifestations of disease. To address the need for a drug capable of suppressing premature termination, we identified PTC124-a new chemical entity that selectively induces ribosomal readthrough of premature but not normal termination codons. PTC124 activity, optimized using nonsense-containing reporters, promoted dystrophin production in primary muscle cells from humans and mdx mice expressing dystrophin nonsense alleles, and rescued striated muscle function in mdx mice within 2-8 weeks of drug exposure. PTC124 was well tolerated in animals at plasma exposures substantially in excess of those required for nonsense suppression. The selectivity of PTC124 for premature termination codons, its well characterized activity profile, oral bioavailability and pharmacological properties indicate that this drug may have broad clinical potential for the treatment of a large group of genetic disorders with limited or no therapeutic options. 相似文献
9.
Lily Campbell Sarah E. Dudas Francis Juanes Travis G. Gerwing 《Journal of Natural History》2020,54(15-16):919-945
ABSTRACT The Skeena River estuary supports commercial and culturally important salmon fisheries. However, considerable development has occurred in the area, and more has been proposed. If anthropogenic development degrades this critical habitat, the Skeena salmon run, that every year contributes $110 million to local economies, may be negatively impacted. Benthic invertebrates are common indicator species, as they often respond to disturbances before commercial species, warning of potential impacts. Unfortunately, invertebrates in the Skeena estuary have not been extensively studied, and we lack the detailed understanding of their community structure and dynamics for them to serve as indicator species in this region. Therefore, present conditions of the Skeena estuary are established here (invertebrate community, sediment conditions and food availability), in order to provide the data required both to anticipate changes associated with potential anthropogenic disturbances and to detect changes in this system if development occurs. 相似文献
10.
Vitart V Rudan I Hayward C Gray NK Floyd J Palmer CN Knott SA Kolcic I Polasek O Graessler J Wilson JF Marinaki A Riches PL Shu X Janicijevic B Smolej-Narancic N Gorgoni B Morgan J Campbell S Biloglav Z Barac-Lauc L Pericic M Klaric IM Zgaga L Skaric-Juric T Wild SH Richardson WA Hohenstein P Kimber CH Tenesa A Donnelly LA Fairbanks LD Aringer M McKeigue PM Ralston SH Morris AD Rudan P Hastie ND Campbell H Wright AF 《Nature genetics》2008,40(4):437-442
Uric acid is the end product of purine metabolism in humans and great apes, which have lost hepatic uricase activity, leading to uniquely high serum uric acid concentrations (200-500 microM) compared with other mammals (3-120 microM). About 70% of daily urate disposal occurs via the kidneys, and in 5-25% of the human population, impaired renal excretion leads to hyperuricemia. About 10% of people with hyperuricemia develop gout, an inflammatory arthritis that results from deposition of monosodium urate crystals in the joint. We have identified genetic variants within a transporter gene, SLC2A9, that explain 1.7-5.3% of the variance in serum uric acid concentrations, following a genome-wide association scan in a Croatian population sample. SLC2A9 variants were also associated with low fractional excretion of uric acid and/or gout in UK, Croatian and German population samples. SLC2A9 is a known fructose transporter, and we now show that it has strong uric acid transport activity in Xenopus laevis oocytes. 相似文献