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31.
P. Schlee R. Graml E. Schallenberger D. Schams O. Rottmann A. Olbrich-Bludau F. Pirchner 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(3-4):497-500
A leucine/valine substitution at amino acid position 127 was identified by the polymerase chain reaction and restriction fragment length polymorphism in the bovine growth hormone gene. Genotyping was performed in 84 AI bulls of three different breeds, in which plasma concentrations of growth hormone (GH) and insulin-like growth factor I (IGF-1) were also measured. Gene frequencies of variants L (leucine) und V (valine) were 0.80/0.20 (Black and White), 0.90/0.10 (Brown), 0.71/0.29 (Simmental). Hormone concentrations were measured during different physiological conditions (normal feeding, fasting, realimentation) in the majority of animals. Generally, genotype LL was associated with higher concentrations of GH than LV. This difference was significant in Black and White bulls (P < 0.05). In contrast, IGF-1 concentrations were higher in LV than in LL animals. This was most pronounced in mature, realimented Simmental bulls. We conclude that the various GH alleles influence the circulating concentrations of GH and IGF-1. 相似文献
32.
Manfred Gahrtz Jürgen Stolz Norbert Sauer 《The Plant journal : for cell and molecular biology》1994,6(5):697-706
In this paper the cloning of a full-length cDNA clone encoding the PmSUC2 sucrose-H+ symporter from Plantago major is described. This plant allows the simple preparation of vascular bundles from the basal regions of fully developed source leaves and thus a separation of vascular and non-vascular tissue. A cDNA library was constructed from poly(A)+ RNA isolated from vascular bundles and used for the subsequent cloning of cDNAs. The respective mRNA is specifically expressed in the vascular bundles as shown on Northern blots of total RNA from vascular and non-vascular tissues. The PmSUC2 protein has 12 putative transmembrane helices and is highly homologous to other plant sucrose transporters. Substrate specificity and energy dependence of the transporter encoded by this cDNA were determined by expression in baker's yeast Saccharomyces cerevisiae. The PmSUC2 protein catalyses the transport of sucrose into transgenic yeast cells. Invertase null mutants of yeast expressing PmSUC2 accumulate sucrose more than 200-fold. This transport was sensitive to uncouplers or SH-group inhibitors. Plasma membranes from yeast cells expressing the PmSUC2 protein were purified and fused to proteoliposomes containing cytochrome-c-oxidase. In this system sucrose is accumulated only when proton motive force is generated, indicating that PmSUC2 is a sucrose-H+ symporter. The apparent molecular weight of the PmSUC2 protein is 35 kDa on 10% SDS-polyacrylamide gels. The presented data strongly support the theory of phloem loading from the apoplastic space by a sucrose-H+ symporter. 相似文献
33.
The separation and quantitation of coumarinic anticoagulant drug enantiomers were achieved by direct chiral capillary electrophoresis using complex maltooligosaccharide mixtures as stereoselective electrolyte modifiers. Chiral separations were characterized by a high selectivity and efficiency, enabling enantiomeric excess determinations. In addition, preliminary results indicate the applicability of the method for the determination of individual enantiomers in biological samples. So the method can be used to perform stereoselective pharmacokinetic studies. © 1994 Wiley-Liss, Inc. 相似文献
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35.
Johannes Battjes Norbert O. E. Vischer Konrad Bachmann 《American journal of botany》1993,80(4):419-428
The positions at which floret primordia arise in developing capitulum buds of Microseris pygmaea D. Don have been mapped by computer-assisted light microscopy. The primordia can be assigned positions along a basic phyllotactic spiral with a divergence angle of about 137.5°. In addition, there are regular deviations from a spiral arrangement. Typically, the first 26 primordia in phyllotactic sequence are arranged in two concentric circles of 13 primordia with considerable deviations in the divergence angle and in the distances between primordia along a parastichy at positions 13 and 26. This arrangement can be simulated by geometric models that include nearest neighbor packing, together with spiral phyllotaxis. The circular arrangement of peripheral primordia at nearly equal radial distances from the center of the developing capitulum helps to explain the numerical constancy (canalization) of peripheral structures, especially the constant number of 13 inner phyllaries on heads with very different numbers of florets. 相似文献
36.
Isolation of U3 snoRNP from CHO cells: a novel 55 kDa protein binds to the central part of U3 snoRNA. 总被引:12,自引:0,他引:12 下载免费PDF全文
U3 snoRNP, the most abundant of the small nucleolar ribonucleoprotein particles (snoRNPs), has previously been demonstrated to participate in pre-rRNA maturation. Here we report the purification of U3 snoRNP from CHO cells using anti-m3G-immunoaffinity and mono Q anion-exchange chromatography. Isolated U3 snoRNPs contain three novel proteins, of 15, 50 and 55 kDa respectively. These proteins may represent core U3 snoRNP proteins whose binding mediates the association of other proteins, such as fibrillarin, that are lost during purification. Using a rabbit antiserum raised against the 55 kDa protein, and an in vitro reconstitution assay, we have localised the 55 kDa protein binding site on the U3 snoRNA. Stable binding of the 55 kDa protein requires sequences located between nucleotides 97 and 204 of the human U3 snoRNA, including the evolutionarily conserved B and C sequence motifs. 相似文献
37.
E. Mark Williams Mogens L. Glass Norbert Heisler 《Environmental Biology of Fishes》1993,37(4):407-413
Synopsis The oxygen transport characteristics and the acid-base status of carp blood was studied in vitro by equilibration of blood samples with and without addition of 5mmol l–1 of nitrite for 30 min at various Po2 values in combination with Pco2 of 1.5 and 5.7mmHg (0.2 and 0.76kPa). After equilibration pH, Po2, Pco2, and Co2 as well as methaemoglobin and HCO3
– concentration were determined and oxygen dissociation curves established. At Pco2 of 1.5mmHg (0.2kPa) oxygen affinity, expressed by a normal P50 of 3.3mmHg (0.44kPa) was unaffected by nitrite exposure, whereas at Pco2 5.7 (0.76kPa), nitrite exposure shifted P50 from 7.59mmHg (1.01kPa) to 21.9mmHg (2.92kPa). Methaemoglobin formation was greater at the higher Pco2 and increased with falling Po2. Erythrocyte shrinkage and rising plasma [HC03
–] during nitrite exposure indicated that the erythrocyte osmoregulation was significantly affected. The present results indicate significantly reduced oxygen affinity upon exposure of carp blood to nitrite. This result contrasts with findings in mammalian blood, where oxygen affinity is greatly enhanced. 相似文献
38.
Dr. Koffi Christophe Kobenan Dr. Ibrahime Sinan Kouadio Dr. Malanno Kouakou Dr. Pierre Silvie Dr. Kra Norbert Bini Kouadio Dr. Kouadio Emmanuel N'goran Dr. Brou Julien Kouakou Dr. Nogbou Ferdinand Amangoua Dr. Kouakou Etienne Tehia Dr. Abdullahi Ibrahim Uba Prof. Dr. Gokhan Zengin 《化学与生物多样性》2023,20(8):e202300411
Faced with the serious consequences resulting from the abusive and repeated use of synthetic chemicals, today rethinking crop protection is more than necessary. It is in this context that the essential oils of the Lamiaceae Ocimum gratissimum and Ocimum canum, the Poaceae Cymbopogon citratus and nardus and a Rutaceae Citrus sp. of known chemical compositions were experimented. The evaluation of the larvicidal potential of the essential oils was done by the method of topical application of the test solutions, on the L1−L2 stage larvae from the first generation of S. frugiperda obtained after rearing in an air-conditioned room. Lethal concentrations (LC10, LC50 and LC90) were determined after 48 h. After assessing the larvicidal potential of essential oils, molecular docking was carried out to study protein-ligand interactions and their propensity to bind to insect enzyme sites (AChE). The essential oil of O. gratissimum was the most effective with the lowest lethal concentrations (LC10=0.91 %, LC50=1.91 % and LC90=3.92 %). The least toxic oil to larvae was Citrus sp. (LC10=5.44 %, LC50=20.50 % and LC90=77.41 %). Molecular docking revealed that p-cymene and thymol from O. gratissimum essential oil are structurally similar and bind to the AChE active site via predominantly hydrophobic interactions and a H-bond with Tyr374 in the case of thymol. The essential oil of O. gratissimum constitutes a potential candidate for the development of biological insecticides for the fight against insect pests and for the protection of the environment. 相似文献
39.
40.
Jürgen Heinze Norbert Lipski Bert Hlldobler 《Ethology : formerly Zeitschrift fur Tierpsychologie》1992,90(4):265-278
Colonies of the ant, Leptothorax (s. str.) gredleri may contain several inseminated female reproductives of which typically only one is laying eggs. Observations suggest that “functional monogyny” is caused by aggressive interactions among nestmate queens. Only the most dominant queen reproduces. Subordinate queens either leave the colony to found their own nests solitarily or by budding, or stay in the nest without reproducing, but may eventually replace the dominant queen. The interrelations of life history of L. gredleri, population structure and habitat characteristics are examined. 相似文献