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排序方式: 共有252条查询结果,搜索用时 15 毫秒
1.
Salas-Prato Milagros Tanguay Jean-Francois Lefebvre Yves Wojciechowicz Don Liem H. Heng Barnes David W. Ouellette Ginette Muller-Eberhard Ursula 《In vitro cellular & developmental biology. Plant》1988,24(5):470-470
In Vitro Cellular &; Developmental Biology - Plant - 相似文献
2.
Sexual dimorphism in the emergence of deciduous teeth: its relationship with growth components in height 总被引:1,自引:0,他引:1
Sexual dimorphism in the emergence of the deciduous dentition of French-Canadian children may be explained by differences in recumbent length. Relative to the chronological age scale, boys are longer and their teeth emerge earlier than girls. Recumbent lengths attained at the exact age of emergence, as estimated by fifth-order polynomials fitted to each subject's serial data, are comparable between the sexes. Multi- and univariate analyses of variance show no significant sex differences in the lengths attained at the age of emergence of the deciduous teeth. These findings suggest that clinical standards for emergence of deciduous teeth scaled relative to length rather than chronological age are more accurate and efficient. 相似文献
3.
Using a specific technique which stains the secondary constriction of number 9 chromosomes in man, we observed that this segment frequently appears to be composed of multiple small units packed together in metaphase as well as in interphase. During prophase of the first meiotic division in man, this segment looks like a diffuse structure, suggesting division and multiplication of these units. On the other hand, the C9 bodies observed in interphase with this cytological procedure are frequently associated with the nucleolus. This heterochromatin is less compact than previously shown and may represent repetitive DNA with a specific role.
Travail subventionné par une bourse nationale du Canada pour la Santé, projet no. 604-7-779. 相似文献
Travail subventionné par une bourse nationale du Canada pour la Santé, projet no. 604-7-779. 相似文献
4.
Population genetics and phylogenetics of DNA sequence variation at multiple loci within the Drosophila melanogaster species complex 总被引:14,自引:1,他引:13
Two regions of the genome, a 1-kbp portion of the zeste locus and a 1.1-
kbp portion of the yolk protein 2 locus, were sequenced in six individuals
from each of four species: Drosophila melanogaster, D. simulans, D.
mauritiana, and D. sechellia. The species and strains were the same as
those of a previous study of a 1.9-kbp region of the period locus. No
evidence was found for recent balancing or directional selection or for the
accumulation of selected differences between species. Yolk protein 2 has a
high level of amino acid replacement variation and a low level of
synonymous variation, while zeste has the opposite pattern. This contrast
is consistent with information on gene function and patterns of codon bias.
Polymorphism levels are consistent with a ranking of effective population
sizes, from low to high, in the following order: D. sechellia, D.
melanogaster, D.mauritiana, and D. simulans. The apparent species
relationships are very similar to those suggested by the period locus
study. In particular, D. simulans appears to be a large population that is
still segregating variation that arose before the separation of D.
mauritiana and D. sechellia. It is estimated that the separation of
ancestral D. melanogaster from the other species occurred 2.5-3.4 Mya. The
separations of D. sechellia and D. mauritiana from ancestral D. simulans
appear to have occurred 0.58- 0.86 Mya, with D. mauritiana having diverged
from ancestral D. simulans 0.1 Myr more recently than D. sechellia.
相似文献
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6.
Katie M. Lebold Christiane V. Löhr Carrie L. Barton Galen W. Miller Edwin M. Labut Robert L. Tanguay Maret G. Traber 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2013,157(4):382-389
We hypothesized that zebrafish (Danio rerio) undergoing long-term vitamin E deficiency with marginal vitamin C status would develop myopathy resulting in impaired swimming. Zebrafish were fed for 1 y a defined diet without (E ?) and with (E +) vitamin E (500 mg α-tocopherol/kg diet). For the last 150 days, dietary ascorbic acid concentrations were decreased from 3500 to 50 mg/kg diet and the fish sampled periodically to assess ascorbic acid concentrations. The ascorbic acid depletion curves were faster in the E ? compared with E + fish (P < 0.0001); the estimated half-life of depletion in the E ? fish was 34 days, while in it was 55 days in the E + fish. To assess swimming behavior, zebrafish were monitored individually following a “startle-response” stimulus, using computer and video technology. Muscle histopathology was assessed using hematoxylin and eosin staining on paramedian sections of fixed zebrafish. At study end, E ? fish contained 300-fold less α-tocopherol (p < 0.0001), half the ascorbic acid (p = 0.0001) and 3-fold more malondialdehyde (p = 0.0005) than did E + fish. During the first minute following a tap stimulus (p < 0.05), E + fish swam twice as far as did E ? fish. In the E ? fish, the sluggish behavior was associated with a multifocal, polyphasic, degenerative myopathy of the skeletal muscle. The myopathy severity ranged from scattered acute necrosis to widespread fibrosis and was accompanied by increased anti-hydroxynonenal staining. Thus, vitamin E deficiency in zebrafish causes increased oxidative stress and a secondary depletion of ascorbic acid, resulting in severe damage to muscle tissue and impaired muscle function. 相似文献
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10.
C García-Vielma MI Dávila-Rodríguez F Hernández-Garza RM Cerda-Flores 《Biotechnic & histochemistry》2016,91(2):102-107
We performed a hospital-based, unmatched case-control study to investigate the association between progressive stages of cervical neoplasia and digital analysis of cell proliferation by silver stained nucleolus organizer region associated proteins (AgNORs). We measured cell proliferation levels in the cervical epithelial cells of 10 women with low grade squamous intraepithelial lesions (LG-SIL), eight with high grade squamous intraepithelial lesions (HG-SIL), 11 with cervical cancer (CC) and eight with no cervical lesions (controls) using the AgNORs technique. Cell proliferation was measured by digital image analysis (DIA). DIA revealed increased total areas of AgNORs in HG-SIL and CC compared to LG-SIL and control patients. AgNORs with a kidney or cluster shape exhibited greater areas than those with a spherical or long shape. We propose a cut-off of 118 pixels to differentiate benign (control and LG-SIL) from malignant (HG-SIL and CC) lesions. DIA of AgNORs is a simple and inexpensive method for studying proliferation. The increased total area of AgNORs in malignant lesions provides information regarding cell behavior and may be related to cervical carcinogenesis; however, further validation studies are required to establish its usefulness in cytological analysis. 相似文献