Signal perception and the integration of signals into networks that effect cellular changes is essential for all cells. The self-incompatibility (SI) response in field poppy pollen triggers a Ca 2 ؉ -dependent signaling cascade that results in the inhibition of incompatible pollen. SI also stimulates dramatic alterations in the actin cytoskeleton. By measuring the amount of filamentous (F-) actin in pollen before and during the SI response, we demonstrate that SI stimulates a rapid and large reduction in F-actin level that is sustained for at least 1 h. This represents quantitative evidence for s timulus-mediated depolymerization of F-actin in plant cells by a defined biological stimulus. Surprisingly, there are remarkably few examples of sustained reductions in F-actin levels stimulated by a biologically relevant ligand. Actin depolymerization also was achieved in pollen by treatments that increase cytosolic free Ca 2 ؉ artificially, providing evidence that actin is a target for the Ca 2 ؉ signals triggered by the SI response. By determining the cellular concentrations and binding constants for native profilin from poppy pollen, we show that profilin has Ca 2 ؉ -dependent monomeric actinsequestering activity. Although profilin is likely to contribute to stimulus-mediated actin depolymerization, our data suggest a role for additional actin binding proteins. We propose that Ca 2 ؉ -mediated depolymerization of F-actin may be a mechanism whereby SI-induced tip growth inhibition is achieved.

Abstract. In project development it is hardly possible to get exhaustive and accurate information. As a result, the situations occur, the consequences of which can be very damaging to the project. Inaccurate evaluation of the strategy related to capital investment and project implementation is one of the reasons why such estimates are not required in practice. Instead, a classification approaches may be used for this purpose. The decision-making process, based on the established risk assessment principles expressed in linguistic terms, requires qualitative judgement and experiential knowledge of the construction experts. Presented structured and realistic methods deals systematically with different risk management situations and assist the investors in reaching the correct risk assessment of possible alternatives will be of great value. This paper presents a methods of multiattribute comparativite analysis (CLARA and SAW methods) of variants of investment classified risks in construction. A practical case to illustrate how the methods works is presented.

The practice of using environmental management systems (EMS) ISO 14001 at the organisational level indicates that the efficacy of such solutions depends on many factors, both endogenous and exogenous in nature. This article aims to identify the fac- tors that determine the opportunities for the improvement of EMS in organisations, the analysis of the relationship between the factors and the classification of the factors due to their role in the system improvement. The structural analysis was used to classify and identify the key factors and then to categorize these factors into five groups. Finally, the role of these key factors in improving environmental management systems was exam- ined. Based on the findings, guidelines can be offered to both scholars and practitioners regarding the factors crucial for the improvement of the EMS. Aiming to add value to the existing literature, the structural analysis was adapted to classification and identification of the key factors. From the point of view of practitioners, it seems to be very profitable to concentrate on the crucial factors during the process of EMS improvement.

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Sexual reproduction in flowering plants is controlled by recognition mechanisms involving the male gametophyte (the pollen) and the female sporophyte (the pistil). Self-incompatibility (SI) involves the recognition and rejection of self- or incompatible pollen by the pistil. In Papaver rhoeas, SI uses a Ca(2+)-based signalling cascade triggered by the S-protein, which is encoded by the stigmatic component of the S-locus. This results in the rapid inhibition of incompatible pollen tube growth. We have identified several targets of the SI signalling cascade, including protein kinases, the actin cytoskeleton and nuclear DNA. Here, we summarize progress made on currently funded projects in our laboratory investigating some of the components targeted by SI, comprising (i) the characterization of a pollen phosphoprotein (p26) that is rapidly phosphorylated upon an incompatible SI response; (ii) the identification and characterization of a pollen mitogen-activated protein kinase (p56), which exhibits enhanced activation during SI; (iii) characterizing components involved in the reorganization and depolymerization of the actin cytoskeleton during the SI response; and (iv) investigating whether the SI response involves a programmed cell death signalling cascade.