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541.
542.
Partial 18S rRNA sequences of five chelicerate arthropods plus a
crustacean, myriapod, insect, chordate, echinoderm, annelid, and
platyhelminth were compared. The sequence data were used to infer phylogeny
by using a maximum-parsimony method, an evolutionary-distance method, and
the evolutionary-parsimony method. The phylogenetic inferences generated by
maximum-parsimony and distance methods support both monophyly of the
Arthropoda and monophyly of the Chelicerata within the Arthropoda. These
results are congruent with phylogenies based on rigorous cladistic analyses
of morphological characters. Results support the inclusion of the
Arthropoda within a spiralian or protostome coelomate clade that is the
sister group of a deuterostome clade, refuting the hypothesis that the
arthropods represent the "primitive" sister group of a protostome coelomate
clade. Bootstrap analyses and consideration of all trees within 1% of the
length of the most parsimonious tree suggest that relationships between the
nonchelicerate arthropods and relationships within the chelicerate clade
cannot be reliably inferred with the partial 18S rRNA sequence data. With
the evolutionary-parsimony method, support for monophyly of the Arthropoda
is found in the majority of the combinations analyzed if the coelomates are
used as "outgroups." Monophyly of the Chelicerata is supported in most
combinations assessed. Our analyses also indicate that the
evolutionary-parsimony method, like distance and parsimony, may be biased
by taxa with long branches. We suggest that a previous study's inference of
the Arthropoda as paraphyletic may be the result of (a) having two few
arthropod taxa available for analysis and (b) including long-branched taxa.
相似文献
543.
C Minimo P H Bartels D H Kim T Pfeifer H E Dytch H Galera-Davidson M Bibbo 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》1991,13(6):411-417
Architectural and histometric features for the objective grading of prostate adenocarcinoma in histologic specimens were analyzed in five cases each of Gleason primary grades 2, 3A, 3B, 3C, 4A and 4B, selected as "typical" for the histopathologic images. Tissue sections from the selected cases were stained by the Feulgen method. Fifteen fields for each grade, for a total of 4,430 glands, were digitized by a video-based microphotometer at low resolution (pixel spacing of 2 microns). Outer and inner outlines of the glandular epithelium were traced manually using a mouse. For each field the number of glands, the gland area, the lumen area, the area of the glandular epithelium and the cribriformity factor were computed. The gland area and its variance proved to be useful indicators for lower-grade lesions, whereas the variance of cribriformity resulted in an excellent grading indicator in the Gleason 3-4 range when cribriform glands were present. 相似文献
544.
545.
546.
Summary The present mapping studies in the gal region of E. coli are a continuation of experiments reported previously (Pfeifer and Oellermann, 1967).By mapping of 238 gal mutants against 145 deletions of the gal region carried by dg phages the kinase gene could be divided into 14 and the transferase gene into 19 deletion groups1. Results of quantitative transduction experiments strongly suggest that there are preferred endpoints for the deletions. 相似文献
547.
Microorganisms associated with Pacific shrimp (Pandalus jordani) were isolated and identified. Those on the iced raw shrimp, which yielded an average count of 1.6 x 10(6), were predominantly Moraxella, Pseudomonas, Acinetobacter, Arthrobacter, and Flavobacterium-Cytophaga spp. The blanching and peeling reduced the microbial level to 3.3 x 10(4) and also selectively eliminated Moraxella spp. The microbial flora changed after each processing sequence, and the heat sensitivity and growth characteristics of the representative microbial groups suggested that the presence of Arthrobacter and Acinetobacter spp. in peeled shrimp may indicate inadequate cleaning of raw shrimp or a shorter blanching time. The presence of Moraxella and Flavobacterium-Cytophaga spp. would indicate the degree of secondary contamination, and the presence of Pseudomonas spp. would indicate the shelf-age of the processed shrimp. 相似文献
548.
F. G. Sulman D. Levy Y. Pfeifer E. Superstine E. Tal 《International journal of biometeorology》1975,19(3):202-209
Changes from normal weather to hot dry heat (Sharav) or cold rainy weather (Bora) evoked specific reactions of neurohormone secretion in 500 female weather-sensitive patients studied in Jerusalem (Israel). Urinary 17-KS increased only during the weather front period, whereas 17-OH increased steadily during the weather front and heat period. Adrenaline and noradrenaline decreased during both the weather front and the following heat period, clinically presenting all symptoms of adrenal medulla exhaustion. Serotonin increased during the weather front period and returned to normal thereafter, whether it was followed by a hot spell or a cold period, whereas 5-HIAA was increased throughout the weather front and hot period. Clinically, serotonin overproduction manifested itself as the serotonin irritation syndrome (migraine, etc.). Patients suffering from occult hyperthyroidism reacted with an increase of urinary thyroxine and histamine as soon as a weather front arrived with the clinical signs of slight hyperthyroidism, especially tachycardia. The serotonin irritation syndrome and the hyperthyroidism were prevented and cured by negative air ionisation treatment in 75% or 45% of the cases respectively. 相似文献
549.
D. Pfeifer H. J. Hirsch D. Bergmann M. Hamlaoui 《Molecular & general genetics : MGG》1974,132(3):203-213
Summary The physical distances between endpoints of deletions in the gal operon of dgal phages previously isolated and mapped by genetic methods have been measured by electron microscopy of heteroduplex DNA. Thus, the galT and galK sites previously mapped by genetic methods, may be assigned to 13 and 4 intervals, respectively, of known physical lengths. The physical data clearly show a nonrandom distribution of these deletion endpoints.On the other hand, a large number of deletions in the gal operon obtained as survivors of a
cI857
lysogenic strain at 42°C also show a non-random distribution of endpoints of deletions in the gal genes. There are at least two sites in the gal genes at which we observed a clustering of endpoints of deletions within the same regions of dgal del-phages and in the bacterial deletion mutants. 相似文献
550.
Two preparations of myelin basic protein (MBP) were derived from an acid excretion of chloroform-methanol defatted bovine spinal cord. The first was purified by ion-exchange chromatography using guanidine-HCl; the second, by high performance liquid chromatography (HPLC) using a triethylamine eluant. Both methods of preparation yield MBP which is identical on acid-urea polyacrylamide gel electrophoresis and which has identical encephalitogenic potency. Because of the greater time-efficiency of the HPLC system with no deleterious side effects due to buffer contamination, this latter method can be recommended for MBP purification. 相似文献