Search results for "pine"
showing 10 items of 2022 documents
Localization and Activity of a Carboxypeptidase in Germinating Seeds of Scots Pine, Pinus sylvestris
1976
Extracts prepared from the endosperm of germinating seeds of Scots pine, Pinus sylvestris L., hydrolysed two typical carboxypeptidase substrates, Z-Phe-Ala and Z-Phe-Phe, with pH optima at 4.2 and 5.0. The activities were completely destroyed by diisopropylfluorophosphate. Identical heat inactivation curves and elution patterns in gel chromatography on Sephadex G-200 suggest that the two activities are due to a single enzyme. In resting seeds very low carboxypeptidase activity was present in both the endosperm and the embryo. During germination on agar gel at 20°C in the dark the activities, expressed as enzyme units per seed, increased in the seedling and particularly in the endosperm up t…
1H,13C and17O NMR spectroscopic study of four bicyclo [3.1.1]heptenes (derivatives of α-pinene) and four bicyclo[3.1.1]heptanes (derivatives of β-pin…
1992
Four derivatives of 2, 6, 6-trimethylbicyclo[3.1.1]hept-2-ene (α-pinene) and four derivatives of 2-methylene-6, 6-dimethylbicyclo[3.1.1]heptane (β-pinene) were synthesized and their 1H, 13C and 17O NMR spectra were measured, analysed and assigned. The 1H NMR spectral parameters were obtained by computer-aided analyses of the very complex multi-spin, second-order spectra. Some of the 13C NMR chemical shift assignments of these compounds reported in the literature should be changed, based on these accurate 1H NMR spectral analyses and carbon-proton chemical shift correlated spectra (COSY). The new assignments are supported by the 1J(C, H) values, which show a strong dependence on the bond ang…
Decomposer animal communities in forest soil along heavy metal pollution gradient
1996
Responses of soil decomposer animals to heavy metal contamination and to concomitant changes in organic matter quality and quantity and in soil microbial biomasses have been studied along a pollution gradient from a Cu-Ni smelter. Samples have been taken separately for nematodes, enchytraeids and microarthropods 0.5, 2 and 8 km from the smelter. Special attention has been paid to the changes in the collembolan fauna. The sampling sites have been located in homogeneous Scots pine ( Pinus sylvestris) forests with podsolic soil profiles. In addition, an experiment has been carried out in which intact soil cores have been transferred in mesh baskets between the sites 2 and 8 km from the smelter…
1-Alkyl- and azeto[1,2-a][1,5]benzodiazepine derivatives in the reaction of o-phenylenediamine with 3-(dimethylamino)propiophenones
2000
The reaction of o-phenylenediamine (4) with one, two or three equivalents of p-substituted 3-dimethylaminopropiophenone hydrochlorides 5a−e was studied. 4-Aryl-2,3-dihydro-1H-1,5-benzodiazepine derivatives 6a−e were obtained in good yields, along with the 1:2-adducts 7c−e and the unexpected 1:3-adducts rac-8c−e. The type of adduct formed is determined by the molar ratio of the reactants 4 and 5 and by the nature of the substituent in the para position of the propiophenone 5.
Characterization of the Proteinases Present in Germinating Seeds of Scots Pine, Pinus sylvestris
1978
Methods were developed to determine proteinase activity in germinating seeds of Scots pine. The assays were based on the liberation of TCA-soluble peptides from haemoglobin at pH 3.7 and from casein at pH 5.4 and pH 7.0; the reaction products were determined by the Lowry method. — Endosperms separated from seeds at the time of rapid storage protein mobilization (seedling length between 20 and 50 mm) showed high proteinase activities in all three assays. Experiments with different inhibitors suggested that at least four enzymes were involved. One of the enzymes resembled mammalian and microbial pepsin-like acid proteinases: the pH optimum was 3.7 and the enzyme was inhibited by pepstatin.—Th…
Localization and Activity of Naphthylamidases in Germinating Seeds of Scots Pine, Pinus sylvestris
1976
Extracts prepared from endosperms of germinating seeds of Scots pine, Pinus sylvestris L., rapidly hydrolysed the β-naphthylamides of L-phenylalanine and L-leucine optimally at pH 6.5 and that of L-arginine at pH 7.7. Disc electrophoresis followed by activity staining showed that the activities were due to two naphthylamidases (aminopeptidases) with different substrate specificities. Seeds were allowed to germinate at 20°C on agar gel in the dark and the activities on the three substrates were assayed from separated endosperms and seedlings at various stages of germination. The activities in the endosperm of resting seeds were relatively high and they remained unchanged throughout the perio…
Factors affecting adventitious bud induction in Pinus elliottii (Engelm.) embryos cultured in vitro
1987
Embryos of slash pine (Pinus elliottii Engelm.) were induced to form adventitious buds when placed in culture on nutrient media supplemented with cytokinin. Buds were induced on media containing Risser & White major salts. The high content in nitrogen of Murashige & Skoog formulation seems to be deleterious for this in vitro system, since morphogenic responses were only promoted when nitrogen concentration was drastically reduced in the macronutrient formulation. Factors such as concentration of cytokinin (6-benzyladenine) and time and method of exposure (liquid or solid induction medium) strongly influenced bud formation and development. The greatest number of buds and shoots were obtained…
Expression of Nitric Oxide Synthase I Determines the Strength of Adrenergic Cyclic GMP Response in the Rat Pineal Gland
1997
In the rat pineal gland the adrenergic cGMP response is not static but changes during postnatal development and depends on environmental lighting conditions. Since the adrenergic cGMP transduction is mediated by stimulation of the enzyme nitric oxide synthase I (NOS I), we investigated whether changes in the strength of adrenergic cGMP response coincide with the expression of NOS I. Using immunoblot analysis, we found that the increase in adrenergic cGMP transduction in the second postnatal week coincides with enhanced NOS I expression. Similarly, we observed that changes in the intensity of adrenergic cGMP transduction under different environmental lighting conditions correspond to NOS I e…
The reaction of 2,4,5,6-tetraaminopyrimidine with chalcones
2000
The reaction of the tetraaminopyrimidine 1 with the chalcones 2a-f yields, in the presence of catalytic amounts of acetic acid, the 1H-pyrimido[4,5-b][1,4]diazepine derivatives 3a-f. The cyclization process consists of a condensation reaction and a Michael type addition.
Synthesis and NMR configurational study of imidazo[2,1-b]thiazoles from 1H-1,4-diazepine-7(6H)-thiones
1993
Abstract A thermal intramolecular cyclization of 1-vinyl2,3-dihydro-3 H -imidazole-2-thiones to imidazo[2,1-b]thiazoles is reported. A heteronuclear correlation study of these systems was made in order to establish the configuration of the products.