ALBERT

Notizen: Molecular investigation of the process of cold acclimation in woody plants has been limited by the superimposition of dormancy-related events on the process of cold tolerance development. To address this limitation, we have used the grape Vitis labruscana L. ev. Concord to develop a system in which the developmental programme of dormancy can be induced seperately from cold acclimation. Using this system we have characterized differential accumulation of several proteins in grape buds during the normally superimposed endodormancy and cold acclimation programmes, and in buds which have entered only the endodormancy programme. A set of 47 kD proteins accumulated during endodormancy without cold acclimation to a level similar to that found in endodormant and cold-acclimated buds, but without any associated increase in bud cold-acclimation level. However, a 27 kD LEA-like protein accumulated only in cold acclimated buds. We conclude that expression of the 47 kD glycoprotein is endodormancy-related, but is not strictly related to the development of cold acclimation, while the 27 kD protein appears to be more specific to cold acclimation. In addition to strengthening the association of LEA-like proteins with cold acclimation, this system allows more specific assessment of cold acclimation-associated phenomena in overwintering buds.

Notizen: In order to understand the causal relation between postglacial rebound and earthquakes, a simple disc load model is used to: (1) calculate stresses induced in the lithosphere and mantle by glacial loading, melting and postglacial rebound; and (2) evaluate the effect of glacial loading/rebound on the failure potential for earthquakes in the upper crust. the dependence of the failure potential and the actual mode of failure on the coefficient of friction, the ambient tectonic stress magnitude/direction, the stress due to the overlying rocks, and lithospheric thickness are investigated. Prominent features of this paper are the inclusion of: (1) a viscoelastic mantle and thus the migration of stress; and (2) the ambient tectonic stress and overburden stress contributions in the calculation of the total stress field.It is assumed that, throughout the Earth, there are optimally oriented pre-existing virtual faults that are initially close to but not at failure; thus, a time-dependent quantity called dFSM (related to the Coulomb-Mohr failure criterion) can be defined such that a negative value of dFSM would advocate faulting or earthquake activities whereas a positive value of dFSM would promote stability.The results indicate that, under all combinations of tectonic stress magnitude and overburden stress, crustal loading promotes fault stability directly underneath the load.Upon the removal of the load, thrust faulting is predicted within the ice margin if the horizontal stress (Sh) induced by the overburden is greater than or equal to the vertical component (Sv) of the overburden stress (1, where =Sh/Sv). Under this condition, theory predicts that faulting or earthquake activity should have reached a maximum immediately after deglaciation.If the horizontal stress induced by the overburden is less than the vertical component of the overburden stress (〉1), then theory predicts fault stability within the ice margin.The theory predicts fault instability both north and south of the ice margin. the mode of failure, however, is completely determined by the value of The trade-off between the tectonic stress magnitude and the overburden stress parameter () is also investigated. It is shown that a larger tectonic stress magnitude can be used to compensate a smaller value of the results of this analysis show that variations in the coefficient of friction, lithospheric thickness and a ductile zone below the upper crust do not significantly affect the above conclusions.

Notizen: In order to understand the causal relation between postglacial rebound and earthquakes, a realistic ice and water load model is used to (1) calculate stresses induced in the lithosphere and mantle by glacial loading, melting and postglacial rebound and (2) evaluate the effect of glacial loading/rebound on the failure potential for earthquakes in the upper crust. The dependence of both the failure potential and the actual mode of failure on the ambient tectonic stress magnitude, the overburden stress, and lithospheric properties are investigated. Prominent features of this analysis are the inclusion of (1) a viscoelastic mantle and thus the migration of stress, and (2) the ambient tectonic stress and overburden stress contributions in the calculation of the total stress field.The spatio-temporal calculations, by a finite-element technique, of upper-crustal stresses and the failure potential for earthquakes indicate that fault stability is invariably enhanced directly beneath the load. For the case where stresses induced by the overburden are such that the horizontal component (Sh) is greater than or equal to the vertical component (Sv) (ζ≥ 1, where ζ= Sh/Sv), the model predicts the onset of thrust faulting and maximum earthquake activities soon after deglaciation is complete (when rebound rates are at a maximum). Observational data support this prediction. Since that time, rebound stresses have been decreasing in magnitude, but they continue to act as a trigger mechanism for optimally oriented pre-existing faults that are otherwise on the verge of failure. If one limits the existence of such faults to lie within the pre-weakened zones of eastern Canada, then the spatial distribution of current earthquakes can also be explained.Perturbations to the magnitude of the tectonic stress components or lithospheric properties do not affect, to any significant extent, the above conclusions.

Notizen: Micellar-enhanced ultrafiltration (MELT) and air stripping were evaluated for surfactant-contaminant separation and surfactant recovery. Two linear alkyl diphenyloxide disulfonate (DPDS) surfactants were evaluated with the contaminants naphthalene and trichloroethylene. A separation model developed from micellar partitioning principles showed a good correlation to batch MEUF studies, whereas flux analysis highlighted concentration polarization effects in relation to hydrophobe length. MEUF effectively concentrated the surfactant-contaminant system (93 to 99 percent retention); however, this did not result in surfactant-contaminant separation. Batch and continuous flow air stripping models were developed based upon air/water ratio, surfactant concentration, and Micellar partitioning; model predictions were validated by experimental data. Sensitivity analyses illustrated the decline in contaminant-surfactant separation with increasing surfactant concentration (e.g., TCE removal efficiency declines from 83 percent to 37 percent as C-16 DPDS concentration increases from 0 to 55 mM). This effect is greater for more hydrophobic contaminants (naphthalene vs. TCE) and surfactants with greater solubilization potential (C16-DPDS vs. C-12 DPDS). The resulting design equations can account for this effect and thus properly size air strippers to achieve the desired removal efficiency in the presence of surfactant micelles. Proper selection and design of surfactant-contaminant separation and surfactant recovery systems are integral to optimizing surfactant-enhanced subsurface remediation.

Notizen: Guanine nucleotide-binding regulatory proteins (G proteins) play an obligatory role in the transmembrane signaling system and are concerned with the neurochemical basis of several psychiatric disorders. We examined the alteration in the mRNA levels of G protein subclasses (Gil α, Gi2 α and Go α) in behavioral sensitized rats using subchronic treatment with methamphetamine (MAP). Adult male Sprague-Dawley rats received intraperitoneal injections of MAP (4 mg/kg) or saline (control) once daily for 14 days. A remarkable increase in the levels of Gi2 α mRNA was observed in both sides of striatum at 48 hours after the last injection of MAP. The changes in the Gi2 α mRNA levels were not significant at two weeks after the last injection of MAP. The levels of Go α and Gil α mRNA were not changed at 48 hours and at two weeks after the last injection of MAP. These results suggest that the changes in the Gi2 mRNA level might be responsible for the reinforcement of the generation of stereotyped abnormal behavior by repeated administration of MAP rather than the persistence of the reverse tolerance phenomenon.

Notizen: Cultured tobacco cells (Nicotiana tabacum L. cv. Wisconsin 38) adapted to NaCl exhibited significant morphological and physiological changes. Adapted cells remained smaller and more isodiametric at maturity than unadapted cells. The vacuole increased in size relative to the cytoplasm and an extensive network of transvacuolar membrane strands developed. These changes altered the surface contact area between the cytoplasm and the vacuole substantially. In addition, the network of Hechtian strands that anchor the cortical structure to the cell wall became more extensively branched possibly facilitating surface contact of the cytoplasm to the extracellular matrix. Many changes in membrane proteins could also be identified after NaCl adaptation. In particular, a 50-kDa protein that is associated with the plasma membrane and tonoplast was induced during adaptation. Immunocytochemical localization indicated that this 50-kDa protein is associated with Golgi vesicles. By immunoscreening using anti-50-kDa antibody, a 1.71-kb cDNA clone (p50C) was isolated from a λ-ZAP cDNA expression library. The sequence of p50C did not show any significant identity with other genes. Because of the very low abundance of the p50C message, quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze p50C gene expression. Immunoblot and quantitative RT-PCR analyses indicated that the expression of this gene is regulated developmentally since the mRNA and protein increased with age in salt-adapted cells but decreased with age in unadapted cells. Also in tobacco plants, p50C mRNA was more abundant in younger leaves than in older leaves. The gene was responsive to NaCl in tobacco cells and to ABA in tobacco seedlings.

Notizen: In Japan, there was an unusually cool and rainy summer in 1993, and an unusually hot and dry summer in 1994. We investigated chemical species in the waters of Lake Biwa during these two years. Samples were collected vertically from stations off Omimaiko in the mesotrophic northern basin and at a dredged area in the eutrophic southern basin, and surface water samples were also collected from three other stations at about one month intervals. We also studied chemical species in precipitation collected at Otsu, on the southeast shore of the southern basin, and sediment cores collected from the southern basin. The features of the lake water were very dependent on the summer climate. In 1993, abundant rain and weak thermal stratification supported high nutrient concentrations in the epilimnion. In 1994, nutrients were depleted and a high transparency and low concentration of chlorophyll a were observed in the epilimnion of the northern basin. This is because the supply of nutrients was limited owing to little rain and a well-developed thermocline. However, a great deal of dissolved reactive phosphorus (DRP) occurred until late August in the southern basin. Local anoxic conditions were extensively developed in 1994, since a large amount of macroalgae grew and regressed in the southern basin owing to a high water temperature (30°C) and decline in the water-level. Presumably DRP was desorbed from ferromanganese oxides that were reduced in the anoxic sediments and the DRP found its way into the lake water. Although it has been reported that the concentration of phosphorus in the lake water had not significantly increased in the last two decades, phosphorus which had steadily accumulated in the sediments had a crucial effect on the quality of the lake water.

Notizen: Screening for mutants deficient in the high affinity system of nitrate uptake was performed using mutagenized M2 population of rice (Oryza sativa, cv. Nipponbare or Kinmaze). For selecting mutants, M2 seedlings were transferred individually to 10 ml solution containing 250 μM potassium nitrate and 500 μM calcium sulphate at 20 or 28°C. After 6 or 24 h, nitrate concentration of the solution was determined with a nitrate selective electrode and the seedlings showing impaired nitrate uptake were selected as nitrate uptake deficient variants. Of 74 variants, three were confirmed to be mutants with low nitrate uptake ability in the M3 generation. Potassium uptake ability also decreased in the mutants. Three mutants were divided into two groups based on the analysis of nitrate reductase (NR, EC 1.6.6.1) activity and chlorate resistance. Two, NUE13 and NUE36, had a lower level of NR activity than the original cultivar and were not resistant to chlorate, while the seedlings of NUE50 had the same level of NR activity as the original cultivar and were more resistant to chlorate than the original cultivar. All mutants were resistant to cesium, a toxic ion analogue for potassium, suggesting that the decreased levels of both nitrate and potassium uptake were coupled to the change of plasma membrane H+-ATPase activity.

Notizen: H6 is an Atriplex nummularia gene having high sequence homology with the algal caltractin (a basal-body-associated calcium-binding protein) gene. Recombinant H6 was expressed at high levels in Escherichia coli. The recombinant protein exhibited an ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid-induced mobility shift during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was able to bind 45Ca2-. An H6 cDNA probe detected three RNA transcripts of 1.3, 2.2 and 2.4 kb, respectively. The levels of these transcripts were regulated by different environmental cues and during developmental stages. The steady state levels of the 1.3-kb mRNA decreased after touch and heat treatments. Expression of the 2.2-kb message correlated with cell proliferation activity. In cultured cells, the highest level of the 2.2-kb message preceeded the peak of mitotic cell division activity. In plants, the 2.2-kb message was detected only in shoot tips that contained meristematic tissues. The 2.4-kb message was detected exclusively in heat-shocked cells. The relationship among the three transcripts is discussed in the context of the possible role of H6 in mediating developmental and environmental signals.

Notizen: The concentrations of limonoid glucosides in orange molasses, a byproduct of citrus juice processing, were measured. The 17-β-D-gluco-pyranoside derivatives (glucosides) of limonin, nomilin, nomilinic acid and obacunone were present and quantified. Orange molasses contained an average of 568 ppm of total limonoid glucosides at 11.8°Brix. Orange molasses (3.8L) contained up to 12.5g of total limonoid glucosides. The molasses could be used as a source for commercial isolation of citrus limonoid glucosides.