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21.
Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
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Kristel Van Steen Nadia Tahri Geert Molenberghs 《Biometrical journal. Biometrische Zeitschrift》2004,46(2):187-202
Until recently, the most common parametric approaches to study the combined effects of several genetic polymorphisms located within a gene or in a small genomic region are, at the genotype level, logistic regressions and at the haplotype level, haplotype analyses. An alternative modeling approach, based on the case/control principle, is to regard exposures (e.g., genetic data such as derived from Single Nucleotide Polymorphisms – SNPs) as random and disease status as fixed and to use a marginal multivariate model that accounts for inter‐relationships between exposures. One such model is the multivariate Dale model. This model is based on multiple logistic regressions. That is why the model, applied in a case/control setting, leads to straightforward interpretations that are similar to those drawn in a classical logistic modeling framework. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
25.
Denitrification with methanol in the presence of high salt concentrations and at high pH levels 总被引:3,自引:0,他引:3
Jan Peter van der Hoek Paul J. M. Latour Abraham Klapwijk 《Applied microbiology and biotechnology》1987,27(2):199-205
Summary In the combined ion exchange/biological denitrification process for nitrate removal from ground water, in which nitrate is removed by ion exchange, the resins are regenerated in a closed circuit by a biological denitrification reactor. This denitrification reactor eliminates nitrate from the regenerant. Methanol is used as electron donor for biological denitrification. To obtain sufficient regeneration of the resins within a reasonable time, high NaCl or NaHCO3 concentrations (10–30 g/l) in the regenerant are necessary. High NaHCO3 concentrations affected the biological denitrification in three ways: a) a slight decrease in denitrification capacity (30%) was observed; b) the yield coefficient and CH3OH/NO3
-–N ratio decreased. When high NaHCO3 concentrations (above 10g NaHCO3/l) were used, the yield coefficient was 0.10–0.13 g VSS/g NO3
-–N and the CH3OH/NO3
-–N ratio was 2.00–2.03 g/g; c) high NaHCO3 concentrations influenced nitrite production. Nitrite is an intermediate product of biological denitrification and with rising NaHCO3 concentrations nitrite accumulation was suppressed. This was explained by the effect of high NaHCO3 concentrations on the pH in the microenvironment of the denitrifying organisms. High NaCl concentrations also resulted in a slight decrease in denitrification capacity, but the second and third effects were not observed in the presence of high NaCl concentrations.Although the pH in the regenerant will rise as a result of biological denitrification, the capacity of a denitrification reactor did not decrease significantly when a pH of 8.8–9.2 was reached. 相似文献
26.
Quantitative estimates of gibberellin A9 in Norway spruce extracts obtained by gas chromatography-mass spectrometry, radioimmunoassay (RIA_ and bioassay were compared after successive purifications of the extracts. The extracts were assayed in several dilutions with and without the addition of standard gibberellin A9, thus showing the effect of extract components on the response of the assays. Radioimmunoassay produced estimates comparable to gas chromatography-mass spectrometry after one purification step by high-performance liquid chromatography. Extracts purified by polyvinylpyrrolidone-column chromatography and solvent partitioning but not high-performance liquid chromatography resulted in inaccurate RIA estimates. The performance of the RIA could be monitored by logit-log transformations of the standard curve and extract dilution curve and by calculating the slope of the standard addition curve. It was, however, not possible to correct for the interference caused by extract components by the standard addition procedure. Quantifications by Tan-ginbozu dwarf-rice bioassay were accurate, but a large and unpredictable variation makes it unsuitable for quantitative determinations.Abbreviations FW
fresh weight
- GA9
gibberellin A9
- GA9–Me
methylated GA9
- GC-MS
gas chromatography-mass spectrometry
- HPLC
high performance liquid chromatography
- MID
multiple-ion detection
- RIA
radioimmunoassay 相似文献
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28.
V
H gene segments represent the products of the repeated duplication and subsequent diversification of a primordial V gene element. It is widely assumed that natural selection, operating via pathogens, has played the dominant role in this process. Here, we screen some 3.7 × 104 C
+
colonies of mitogen-activated B cells for the production of antibodies specific for phosphorylcholine or hen egg lysozyme and expression of the V
H X-24, S107, Q52, or J558 gene families. These gene families were expressed at frequencies proportional to their genomic complexity among both unselected and antigen-specific C
+
colonies. Thus, the capacity to encode equivalent antibody-combining sites is dispersed uniformly among V
Hfamilies. This result suggests that individual V
H genes have not evolved to address specific antigens. 相似文献
29.
Miroslav Pátek Jan Nešvera Jitka Hochmannová 《Applied microbiology and biotechnology》1989,31(1):65-69
Summary Four hybrid plasmids were constructed from the cryptic plasmid pAM330 (from Brevibacterium lactofermentum; 4.5 kb) and the broadhost-range plasmid pGV1106 (9.0 kb; Kmr Smr) isolated from Escherichia coli. All of them were mobilized from E. coli into the Gram-negative methylotrophic bacterium Methylobacillus sp. and two of these constructs (pCEM300 and pCEM400) were transferred by transformation into B. flavum and Corynebacterium glutamicum. Their kanamycin-resistance determinant coming from Gram-negative hosts was expressed in these Gram-positive bacteria. Both pCEM300 and pCEM400 are very stably maintained in B. flavum and represent suitable vectors for gene cloning in coryneform producers of amino acids. 相似文献
30.
Isolation and structure of corazonin, a cardioactive peptide from the American cockroach 总被引:11,自引:0,他引:11
Corazonin, a new cardioaccelerating peptide, has been isolated from the corpora cardiaca of the American cockroach, Periplaneta americana, and its structure determined to be Glp-Thr-Phe-Gln-Tyr-Ser-Arg-Gly-Trp-Thr-Asn-amide. The peptide stimulated heart beat at concentrations as low as 0.2 nM, which makes it the most potent insect cardioactive neuropeptide. 相似文献