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21.
L.Charles Dickinson James C.W. Chien 《Biochemical and biophysical research communications》1973,51(3):587-592
Single crystals of horse CoHb were obtained by reduction of CoHb+ crystals with dithionite. Epr measurements showed that the g? and Coà tensors are both axial and share the same principal axis systems. Of the four subunits, the “heme” normals of C? and d? subunits ãb?plane 29 ± 1° from b?; they have the same orientation as the hemes in methemoglobin. The normals of “hemes” à and B? are 47 above the ãb? plane as compared to 16° in methemoglobin. 相似文献
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25.
Christine M. Kampny Timothy A. Dickinson Nancy G. Dengler 《American journal of botany》1994,81(10):1343-1353
Intraspecific variation in floral development was studied in four morphologically distinct strains of Pseudolysimachion longifolium and two of P. spicatum. Size increase of whole buds from living plants of P. longifolium was followed in absolute time. Growth rates were homogeneous within inflorescences and within individual plants, and significantly different between individual plants. Organ growth trajectories (plotted as organ size over gynoecium size) differed little among individuals of Pseudolysimachion belonging to morphologically distinct strains; variation was most pronounced in the calyx. Corolla tube as well as calyx and corolla lobe measurements varied more during the early stages of development than near maturity, suggesting constraints on mature flower form. In addition to intraspecific variation, floral development in Pseudolysimachion was compared with that in related Veronica chamaedrys and Veronicastrum virginicum, using data from a previous study. Mature flowers of Pseudolysimachion have long corolla tubes similar to those of Veronicastrum and long corolla lobes similar to those of Veronica. The trajectories of most organs of Pseudolysimachion were intermediate between those of Veronica and Veronicastrum in position as well as in type of curve, i.e., different trajectories lead to similar end products; thus, the shapes of the mature organs are not strictly homologous and not indicative of close relationship. 相似文献
26.
N. Wald M. Law T. Meade G. Miller E. Alberman J. Dickinson 《BMJ (Clinical research ed.)》1994,309(6966):1422-1424
The established practice of doctors using medical records for research purposes is threatened by the recent proposed guidelines from the Department of Health, the BMA, and the European Commission. The European Commission has proposed that explicit consent should be obtained from each patient before his or her medical records can be used; the proposals from the Department of Health and the BMA would require all research that needs access to personal medical records to be submitted to an ethics committee. We believe that these proposals would seriously impair an entire category of research and suggest therefore that another set of guidelines, proposed by a Royal College of Physicians'' working group, should be used to modify the proposals. The guidelines of the working group encourage the use of medical records for research and ensure that such use can be made in a confidential manner without causing harm. 相似文献
27.
Patrick A. Thorpe Janella Loye Cynthia A. Rote W. J. Dickinson 《Journal of molecular evolution》1993,37(6):590-599
In an effort to understand the forces shaping evolution of regulatory genes and patterns, we have compared data on interspecific differences in enzyme expression patterns among the rapidly evolving Hawaiian picture-winged Drosophila to similar data on the more conservative virilis species group. Divergence of regulatory patterns is significantly more common in the former group, but cause and effect are difficult to discern. Random fixation of regulatory variants in small populations and/or during speciation may be somewhat more likely than divergence driven by selection. Within the picture-winged group, we also have compared enzymes that fulfill different metabolic roles. There are highly significant differences between individual enzymes, but no obvious correlations to functional categories.
Correspondence to: W.J. Dickinson 相似文献
28.
W. J. Dickinson Yifan Yang Kim Schuske Michael Akam 《Evolution; international journal of organic evolution》1993,47(5):1396-1406
We are using patterns of cuticle specialization in Drosophila larvae as models to investigate the molecular, genetic, and developmental bases of morphological evolution. Members of the virilis species group differ markedly from one another in the distribution of hairs on the dorsal surface of first instar larvae. In particular, characteristic bands of hairs cover about 20% of each trunk segment in some species but about 70% in others. These major types do not correlate with recently proposed phylogenetic relationships, suggesting that similar phenotypes have arisen independently in different lineages. The patterns of expression of several genes that control or reflect intrasegmental patterning are indistinguishable in species with very different cuticle morphologies. We conclude that, in this case, morphology probably has evolved via altered response to a conserved molecular prepattern. 相似文献
29.
A total of 522 girls and their families from low and middle social strate were examined in the northern part of Merida (Yucatan)
during 1988 and 1989. Marital radius in the parental generation was relatively long (146 km), and it was six times longer
for non-Maya and mixed couples than Maya.
Living and housing conditions were similar for both Maya and non-Maya (mixed couples typically had an intermediate condition),
except for sewage system (sanitation). The Maya income was 64% lower. Maya men and women were short. The girls from Merida
were short, hyper-brachycephalic (short headed), and europrosopic (broad face). Among them, Maya girls were even shorter,
more round-headed, and more broad-faced than non-Maya girls.
Menarche occurred on the average at an age of 12.6 years in mothers and 12.1 years in daughters. As the generation time was
about 25 years, there was a slow acceleration of maturation (0.2 years per decade). Presumably, also stature has increased
in recent years. 相似文献
30.
Use of the polymerase chain reaction and 16S rRNA sequences for the rapid detection of Brochothrix spp. in foods 总被引:5,自引:2,他引:3
K.A. Grant J.H. Dickinson M.J. Payne Shona Campbell M.D. Collins R.G. Kroll 《Journal of applied microbiology》1993,74(3):260-267
Oligonucleotide primers were designed against rRNA sequences to give a DNA-based PCR assay for the rapid identification/detection of Brochothrix spp. The PCR products could be confirmed by hybridization to an internal oligonucleotide probe. The method successfully and sensitively detected/identified these organisms in pure cultures but was of limited value as a detection method because the detection sensitivity, in relation to conventional plate counts, varied and the assay sensitivity was reduced in the presence of staphylococci. Furthermore, sensitivity was also lost when the assay was applied directly to meat samples. However, a separation step using a lectin (from Agaricus bisporus ) immobilized on magnetic beads prior to the PCR assay, allowed the direct detection of low numbers (> 10 cfu g-1 ) of Brochothrix in meat samples within a working day. 相似文献