Expression analysis of the plasma membrane H+-ATPase pma4 transcription promoter from Nicotiana plumbaginifolia activated by the CaMV 35S promoter enhancer

pma4 is the major plasma membrane H+-ATPase gene in Nicotiana plumbaginifolia. To study its physiological role by overexpression, we evaluated the possibility of enhancing the pma4 transcription promoter using a 165-bp enhancing sequence of the CaMV 35S transcription promoter. This was inserted into the pma4 promoter either 500 or 50 nucleotides upstream from the transcription start site. Transient expression with the gusA reporter gene showed that both enhanced pma4 promoters had a 4- to 13-fold greater transcription activity than the native pma4 promoter. Quantitative analysis of stable transgenic plants also showed that both enhanced pma4 promoters conferred much greater GUS activity. Histochemical assay showed that the enhanced promoters produced strong GUS activity in most cell types as already observed in the 35S or the native pma4 promoter. In the cell types where either the 35S or pma4 promoter was inactive, the enhanced promoters mimicked expression of the active one. However, there were cases (e.g. root cortex of seedlings) where, although both 35S and pma4 promoters were active, none of the enhanced promoters induced GUS activity. This might indicate the interference of promoter regulatory elements. The two enhanced pma4 promoters conferred similar expression throughout the plant development, implying that there was no regulatory element at either the pma4 -500 or -50 position, that conferred important tissue specificity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved

Connected learning communities : a model for transnational education

This article reports on the first results of the educational model piloted in EUTOPIA, a transnational university alliance established under the European University initiative. We discuss the theoretical underpinnings and core principles of our model which seeks to enable students, academics and societal partners to form Connected Learning Communities (CLCs) through enhancing existing learning activities and practices in teaching and learning. We elaborate on the value added of our model for developing a diverse portfolio of activities and a dynamic structure that has the potential to offer international learning opportunities to large and diverse group of students, academic staff and societal partners. We close the article with recommendations for the results of European University Alliance pilots to reach their full innovation potential

Identification and characterization of a second plasma membrane H(+)-ATPase gene subfamily in Nicotiana plumbaginifolia

A cDNA clone was isolated for a fourth pma gene encoding a putative plasma membrane H(+)-ATPase of Nicotiana plumbaginifolia. The sequence of the predicted 952 residue PMA4 polypeptide was compared with those of other known plant PMAs, revealing a higher identity with the Arabidopsis thaliana proteins (86-89%) than with the other three N. plumbaginifolia PMA proteins (80-82%). This supports the view that there are two pma subfamilies which probably arose from a gene duplication predating the separation of the Dilleniidae and Asteridae plant subclasses. Measured pma4 transcript levels indicate that pma4 is similarly expressed in root, stem, leaf, and flower tissues, contrary to the pmal-3 subfamily whose members displayed differential expression according to the organ

Dynamic mechanical properties of cold rolled TRIP steels for crash-relevant applications

C

Expression analysis of two gene subfamilies encoding the plasma membrane H+-ATPase in Nicotiana plumbaginifolia reveals the major transport functions of this enzyme.

The plasma membrane H+-ATPase couples ATP hydrolysis to proton transport, thereby establishing the driving force for solute transport across the plasma membrane. In Nicotiana plumbaginifolia, this enzyme is encoded by at least nine pma (plasma membrane H+-ATPase) genes. Four of these are classified into two gene subfamilies, pma1-2-3 and pma4, which are the most highly expressed in plant species. We have isolated genomic clones for pma2 and pma4. Mapping of their transcript 5' end revealed the presence of a long leader that contained small open reading frames, regulatory features typical of other pma genes. The gusA reporter gene was then used to determine the expression of pma2, pma3 and pma4 in N. tabacum. These data, together with those obtained previously for pma1, led to the following conclusions. (i) The four pma-gusA genes were all expressed in root, stem, leaf and flower organs, but each in a cell-type specific manner. Expression in these organs was confirmed at the protein level, using subfamily-specific antibodies. (ii) pma4-gusA was expressed in many cell types and notably in root hair and epidermis, in companion cells, and in guard cells, indicating that in N. plumbaginifolia the same H+-ATPase isoform might be involved in mineral nutrition, phloem loading and control of stomata aperture. (iii) The second gene subfamily is composed, in N. plumbaginifolia, of a single gene (pma4) with a wide expression pattern and, in Arabidopsis thaliana, of three genes (aha1, aha2, aha3), at least two of them having a more restrictive expression pattern. (iv) Some cell types expressed pma2 and pma4 at the same time, which encode H+-ATPases with different enzymatic properties

Platelet anti-aggregant and rheological properties of piracetam. A pharmacodynamic study in normal subjects.

The random administration of four different single oral doses of piracetam (Nootropil, CAS 7491-74-9)--1.6 g, 3.2 g, 4.8 g and 9.6 g--at fixed intervals of 2 weeks to 5 healthy subjects has confirmed and explicited its platelet anti-aggregant and rheological properties after doses of 4.8 g and 9.6 g. The effect on platelet aggregation occurs through inhibition of thromboxane synthetase or anti-thromboxane A2 activity together with a reduction in the plasma level of von Willebrand's factor (F.VIIIR:vW). The rheological effect is related to the action of piracetam on cell membrane deformability (red cells, white cells and platelets) and to its simultaneous effect in reducing by 30-40% plasma levels of fibrinogen and von Willebrand's factor. In addition, it exerts a direct stimulant effect on prostacyclin synthesis in healthy endothelium. These effects are greatest between 1 and 4 h after dosage, and then diminish progressively to disappear between 8 and 12 h after administration. This explains the need to divide the total daily dose into 3 intakes at 8-hourly intervals. This study confirms the presence of four sites of action of piracetam: the vessel wall, platelets, plasma and cell membranes (RBC, WBC), which provide the basis for the potentially important antithrombotic activity of piracetam

Treatment of the Raynaud's phenomenon with piracetam.

Piracetam (Nootropil, CAS 7491-74-9) has been investigated in the treatment of primary and secondary Raynaud's phenomenon in three sequential and complementary studies. The first study in 20 patients with primary Raynaud's phenomenon, utilising clinical and ultrasound examination, capillaroscopy and laboratory tests established a daily dose of 8 g as most effective. The second study in 58 patients (47 primary, 11 secondary) confirmed the therapeutic efficacy of piracetam in both primary and secondary Raynaud's phenomenon. The third study, of crossover design, in 30 patients with severe Raynaud's syndrome, examined various agents given singly or in combination. The results not only confirmed the efficacy of piracetam but in addition allowed comparison of the efficacy of the principal therapeutic agents or regimens used in the treatment of Raynaud's syndrome and the formulation of a list of these therapies in decreasing order of efficacy, thus: piracetam 4 g/d + buflomedil 600 mg/d; piracetam 8 g/d; buflomedil 600 mg/d; piracetam 4 g/d + acetylsalicylic acid 100 mg/d; pentoxifylline 1200 mg/d; calcium antagonists; ketanserin 120 mg/d. The particular efficacy of 8 g piracetam daily in 3 divided doses at 8-hourly intervals can be attributed to its unique dual mode of action; inhibition of platelet function by inhibition of thromboxane A2 synthetase or antagonism of thromboxane A2 and increased formation of prostaglandin I2, together with a rheological effect involving reduction in blood and plasma viscosity through an increase in cell membrane deformability and a reduction of 30-40% in the plasma concentrations of fibrinogen and von Willebrand's factor. In addition, the administration of piracetam appears to be devoided of adverse effects