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21.
Leaf protoplasts were isolated from shoot cultures of two hybrid poplar clones (Populus alba × P. grandidentata Crandon, NC-5339 and P. nigra Betulifolia × P. trichocarpa, NC-5331) and the Upright European Aspen (P. tremula Erecta) and were cultured in contact with screen discs floated in liquid medium. Protoplast culture was influenced by the growth medium of the source shoot cultures, the protoplast purification procedure, the plating density, and the presence or absence of a coconut water and casein hydrolysate supplement added to the culture medium. The protoplast-derived cells divided more quickly and with higher incidence than previously reported for hybrid poplars. Shoots were regenerated from the protoplast-derived calli and were maintained as shoot cultures. Plants were developed from microcuttings rooted ex vitro and were grown-on in the greenhouse and field.Abbreviations BA
benzyladenine
- NAA
1-naphthaleneacetic acid
- TDZ
thidiazuron
- WPM
Woody Plant Medium, Lloyd and McCown (1980)
- MS
Murashige and Skoog Medium (1962)
- NC-XXXX
North Central Forest Experiment Station accession number assigned to hybrid poplar clones. 相似文献
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23.
Morphological dispersion of introduced Hawaiian finches: evidence for competition and a Narcissus effect 总被引:2,自引:0,他引:2
Summary Morphological analyses were conducted on finch species introduced to Oahu, Hawaii. As many as 25 species of finches representing four families (Emberizidae, Fringillidae, Ploecidae, Estrildidae) have been introduced to Oahu. Of these, 15 species currently have established wild populations. When compared with pools of 25 and 23 species introduced to Oahu, the 15 surviving species are morphologically overdispersed. This result is consistent with the hypothesis that competition has influenced the outcome of these introductions. We also tested the hypothesis that surviving introduced finches in one habitat (sugarcane fields) were morphologically overdispersed. When the seven surviving finch species found in sugarcane were compared with the pools of 25 and 23 species, they too were morphologically overdispersed. However, when the seven sugarcane species were compared with a species pool consisting of only the surviving 15 species found across Oahu, they were not morphologically overdispersed. This result suggests that morphological analyses of community structure based only on comparisons of assemblages of surviving species may be biased by a Narcissus effect. 相似文献
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26.
Nuclear genome characterization of the carrageenophyteAgardhiella subulata (Rhodophyta) 总被引:2,自引:0,他引:2
Donald F. Kapraun Julie A. Dutcher Juan Lopez-Bautista 《Journal of applied phycology》1992,4(2):129-137
DNA reassociation kinetics were used to determine nuclear genome organization and complexity inAgardhiella subulata (Gigartinales, Rhodophyta). Results indicate the presence of three second-order components corresponding to fast (22%), intermediate
(68%) and slow (10%) fractions. Thus, the genome consists of 90% repetitive sequences. Microspectrophotoometry with the DNA-localizing
fluorochrome DAPI was used to confirm ploidy level differences in the gametophytic and tetrasporophytic phases. Results indicate
that meiosis occurs during tetrasporogenesis. Comparison of mean nuclear DNA (If) values to chicken erythrocytes (RBC) resulted in an estimate of 0.9 pg/2C genome forAgardhiella. Karyological studies using aceto-orcein revealed a chromosome complement of 2N = 44 in carposporangia and the presence of 22 bivalents during diakinesis of tetraspore mother cells. 相似文献
27.
The malmö polymorphism of coagulation factor IX, an immunologic polymorphism due to dimorphism of residue 148 that is in linkage disequilibrium with two other F.IX polymorphisms 下载免费PDF全文
John B. Graham Dennis B. Lubahn Susan T. Lord Julie Kirshtein Inga Marie Nilsson Anders Wallmark Rolf Ljung L. D. Frazier Jerry L. Ware Shu Wah Lin Darrell W. Stafford John Bosco 《American journal of human genetics》1988,42(4):573-580
A mouse monoclonal antibody (MAB 9.9) to coagulation factor IX (F.IX) detects a polymorphism in the plasma of normal people. Its epitope has been narrowed down to <6 amino acids in the activation peptide of the X-linked F.IX protein. The activation peptide contains a dimorphism—Thr:Ala—at position 148 of the protein. Using synthetic oligonucleotides, we have demonstrated that (1) the F.IX which reacts with 9.9 has Thr at position 148 and (2) that which does not has Ala. Positive reactors (148thr) are designated Malmö A, and negative reactors (148ala) are designated Malmö B. The plasma levels of AA women are indistinguishable from those of A men, and both B men and BB women are null against MAB 9.9. The plasma level of Malmö A in AB women is approximately half that of AA women, and “lyonization” is clearly operating in the heterozygotes. The dimorphism is in strong linkage disequilibrium with two other intragenic RFLPs, TaqI and XmnI. Furthermore, intragenic crossing-over—including double crossing-over—appears to have occurred between the three sites. Seven of the eight possible haplotypes have been identified, five in men and two others in women. The immunoassay that identifies ~50% of the AB women in the pool of Malmö A females with 95% confidence identifies men unambiguously as A or B. The assay would be very useful for population-genetic studies of the Malmö epitope if the studies were limited to men. 相似文献
28.
F Antonicelli B Rothhut L Martiny G Aguie-Aguie B Lambert G Bellon F Russo-Marie C Jacquemin B Haye 《FEBS letters》1988,235(1-2):252-256
A 32 kDa phospholipase A2 inhibitory protein was isolated from pig thyroid gland after calcium precipitation and fast protein liquid anion-exchange chromatography. SDS-polyacrylamide gel electrophoresis revealed the purity of the protein. The protein activity was assessed by the inhibition of pancreatic phospholipase A2 on [3H]oleic acid-labelled Escherichia coli membranes as substrate and on the prostaglandin E2 production of cultured thyroid cells. The amino acid composition and the isoelectric point were quite similar to those of endonexin previously described in other tissues or cells. The cross-reactivity of a polyclonal antibody against a 32 kDa lipocortin from human peripheral blood mononuclear cells with our thyroidal 32 kDa protein confirmed its lipocortin nature. Before the purification by fast protein liquid chromatography, the Ca2+ pellet contained lipocortin I (35 kDa and its core protein 33 kDa) identified by its cross-reactivity with a polyclonal antibody. 相似文献
29.
A deoxyribonuclease was partially purified from the free-living nematodeCaenorhabditis elegans. The DNase functioned as an endonuclease and introduced both single-strand nicks and double-strand breaks into DNA. The enzyme
hydrolyzed double-stranded DNA seven times more rapidly than single-stranded DNA. DNase activity was not affected by the addition
of divalent cations below 1mm but was inhibited at higher ionic concentrations. In addition, the enzyme was not inhibited in the presence of 10mm EDTA. The enzyme was inhibited by salt concentrations greater than 20mm. Three independent mutations in thenuc-1 gene were shown to reduce nuclease activity to less than 1% of that seen in wild-type organisms.
This work was supported by National Institutes of Health Grant AG03161 and a TCU Research Foundation Grant. Some stocks used
in these experiments were obtained from theCaenorhabditis Genetics Center, which is supported by Contract NOI-AG-9-2113 between the NIH and the curators of the University of Missouri. 相似文献
30.
The respective effects of cholera and Bordetella pertussis toxins were studied in time and concentration dependent experiments, following glycerol and fatty acid release, GTP and cAMP levels. Cholera toxin, after a lag time of 30 min, stimulated linearly GTP and cAMP accumulation and lipolysis (maximal effect: 2-fold increase at 5 micrograms/ml). Pertussis toxin presented a biphasic effect both in time and concentration dependent studies. Up to a maximum reached after 2 h with 1.4 units LPF/ml the stimulation affected GTP (3 fold) and cAMP (7 fold) levels, glycerol and fatty acid release (15 fold). Beyond this, an inhibition occurred, yielding a decrease towards basal values of GTP and cAMP content whereas the glycerol and fatty acid release was stopped. These results, which are the first reporting the fluctuation of the GTP content of intact cells challenged with bacterial toxins, show a close relationship between GTP and cyclic AMP levels and lipolytic activity. 相似文献