Martin Gregor

Use of FITC as a Fluorescent Probe for Intracellular pH Measurement

Fluorescein Isothiocyanate (FITC) is widely used in biology and medicine as a fluorescent marker for labeling various proteins. Particularly fluorescence marking of antibodies could not be imagined without FITC. However, at the same time FITC displays pH-indicative properties. This paper evaluates the limits of the use of FITC as a pH indicator in biological material, namely, for intracellular and intraorganellar pH measurement.

Public sector efficiency in transition and beyond: evidence from Czech local governments

This article provides the first comparison of public sector efficiency in and beyond transition. We compare the comprehensive efficiency scores of 202 local governments in the Czech Republic in the transition period of 1995–1998 and the post-transition period of 2005–2008 and identify the period-specific determinants of local government efficiency. We observe convergence to the best practice frontier but also a growing efficiency gap between small and large governments. In both periods, municipal size and the main fiscal variables qualitatively affect efficiency in the same direction and in line with the fiscal stress hypothesis. Left-wing ideology is only robustly associated with cost inefficiency in the transition period. The geographic distances begin to matter for efficiency only in the post-transition period.

The Strategic Euro Laggards

A government applying for a club membership may strategically delay entry to cope with the hold-up problem introduced by anticipatory investments of the private sector. In equilibrium of a two-period incomplete information game, we find that a pro-entry government may strategically delay to imitate an anti-entry government and thereby affect expectations of the private sector. The delay is more likely if the government has a good electoral prospect, is internationally weak, and is not considered to be too keen on entry. The model is related to the case of the Czech Republic where the government recently softened commitment in the euro adoption strategy.

The decentralization tradeoff for complementary spillovers

We examine a symmetric two-district setting with spillovers of local public spending where a spill-in from the foreign spending is not a substitute, but a complement to domestic spending. Specifically, we assume production of two district-specific public goods out of two complementary district-specific inputs. We compare equilibria in non-cooperative decentralization and cooperative centralization for different spillovers, complementarities and cost-division rules, and control for the effects of strategic delegation and the feasibility of voluntary contributions to the input in the foreign district. We find that centralization welfare-dominates decentralization in most institutional settings and for a wide range of parameters, yet we can also identify necessary and sufficient conditions for decentralization to welfare-dominate centralization. The setup features three novelties: In the absence of transfers, welfare in decentralization increases in spillovers, strategic delegation in decentralization improves welfare, and centralized provision may be non-monotonic in spillovers.

Modeling Positive Inter-Jurisdictional Public Spending Spillovers

This paper builds spatial microfoundations for the functional forms used in the analysis of inter-jurisdictional public spending spillovers. It introduces a symmetric bilateral model that distinguishes between three stages: production of multiple public inputs (intermediary goods), production of multiple public outputs (final goods) including asymmetries and non-additive aggregations, and consumption of the public outputs with asymmetries and preferences for variety. The model is characterized by seven modeling features, and the paper demonstrates how these features are combined in the relevant literature. The paper identifies sufficient conditions for the different combinations of the features to be isomorphic. Additionally, it analyzes which microfoundations for the inter-jurisdictional spillovers lead to asymmetrically structured demands for public spending.

Corporate Lobbying: A Review of the Recent Literature

This survey covers recent literature on lobbying, with particular focus on corporate lobbying. Three main research traditions --- contestsfor policy rent, persuasion games, and multiple means models --- are analyzed in detail. Various strategic aspects of lobbying arepresented in the context of a single unified model that encompasses both strategic communication and monetary contributions. Next, thereview investigates into three particular issues in the lobbying literature: (i) Incentive to lobby and the equilibrium amount of lobbying,both in the presence and absence of competitors, (ii) strategic substitution and complementarity of lobbying and contributions,and (iii) the role of intermediation in lobbying. Recent evidence from corporate lobbying is presented.

Civic initiatives in the context of legal uncertainty

In this article, we analyse initiatives organized by groups outside of formal politics that involve political confrontation with elected officials, and the need for recourse to the courts. We show that a civic initiative submitted by a proposer gives the voter not only the option to constrain the mayor but also the possibility of learning the mayor’s type from the signals conveyed in the legal contest over the validity of the initiative. We show that, ex ante, signalling in the context of legal uncertainty improves responsiveness. In addition, our setup identifies limits to empirical inference based on linear models: first, having a more adversarial mayor can lead to either the introduction or the withdrawal of an initiative; second, although initiatives effectively constrain incumbents, they do not necessarily imply increasing distrust in incumbents. Examples from Central European countries are used to illustrate how our model corresponds to real-world conditions.

Inefficient Centralization of Imperfect Complements

If local public goods exhibit spillovers and regions are sufficiently symmetric, decentralization implies underprovision, whereas cooperative centralization is associated with strict Pareto-improvement. This classic inference rests on two assumptions: local politicians are delegated sincerely and never provide voluntary transfers to the other regions. We abandon these assumptions in a setup of two symmetric regions with imperfect complementarity between local public goods. For this particular aggregation, non-cooperative decentralization can achieve the social optimum, whereas cooperative centralization cannot.

Fluorescent Probes in Biology and Medicine. Measurement of Intracellular pH Values in Individual Cells.

The application possibilities of fluorescent probes have increased dramatically in the last few years. The main areas are as follows (Slavik, 1994, 1996, 1998). Intracellular ionic cell composition: There are selective ion-sensitive dyes for H+, Ca2+, Mg2+, K+, Na+, Fe3+, Cl-, Zn2+, Cd2+, Hg2+, Pb2+, Ba2+, La3+. Membrane potential: Using the so-called slow (Nernstian dyes) or electrochromic dyes one can assess the value of the transmembrane potential. Membrane fluidity: Fluorescent probes inform about the freedom of rotational and translational movement of membrane proteins and lipids. Selective labeling: Almost any object of interest inside the cell or on its surface can be selectively fluorescently labeled. There are dyes specific for DNA, RNA, oligonucleotides (FISH), Golgi, endoplasmic reticulum, mitochondria, vacuoles, cytoskeleton, etc. Using fluorescent dyes specific receptors may be localized, their conformational changes followed and the polarity of corresponding binding sites accessed. The endocytic pathway may be followed, enzymes and their local enzymatic activity localized. For really selective labeling fluorescent labeled antibodies exist. Imaging: One of the main advantages of fluorescence imaging is its versatility. It allow choice among ratio imaging in excitation, ratio imaging in emission and lifetime imaging. These approaches can be applied to both the classical wide-field fluorescence microscopy and to the laser confocal fluorescence microscopy, one day possibly to the scanning near field optical microscopy. Simultaneous application of several fluorescent dyes: The technical progress in both excitation sources and in detectors allows to extend the excitation deeper in the blue and ultraviolet side and the detection further in the NIR and IR. Consequently, up to 6 peaks in excitation and up to 6 peaks in emission can be followed without any substantial difficulties. Application of dyes such with longer fluorescence lifetimes such as rare earth dyes gives chance for the separated detection of another six peak pairs. The literature data on simultaneous applications of several fluorescent dyes are rare, usually it is only pH and calcium, pH and membrane potential or pH and cytoskeleton changes that are mentioned. Nevertheless, I am sure that in the near future it will be quite common to employ several fluorescent dyes simultaneously. So, in a few years, you may expect to be comfortably seated in an armchair in front of the monitor screen, sip your coffee and follow simultaneously several physiological parameters trying to find out new relations among them. In this respect the potential of fluorescent probes is unsurpassed if you just recall only the discovery of calcium waves and calcium spikes during the past years.

The Effect of Lysosomal pH on Lactoferrin-Dependent Iron Uptake in Tritrichomonas foetus

Tritrichomonas foetus is a parasitic protozoan which causes a sexually transmitted disease of cattle. The establishment of infection depends on the ability of T. foetus to acquire iron from the host as was demonstrated in experimentally infected mice1. Most of the iron available in mucosal secretions, the environment colonised by this parasite, is rather firmly bound to host iron-binding proteins such as lactoferrin and transferrin. Trichomonads as well as other pathogens therefore evolved specific mechanisms which allow them to withdraw iron from these proteins2,3,4. It was shown recently that lactoferrin is specifically bound to the surface of T. foetus, endocytosed and transported into hydrolase containing lysosome-like organelles5. Although there is no direct evidence for release of iron within this cell compartment, the low pH in the lysosomes might provide a suitable environment for such process. Since information about the intracellular pH of protozoa is rather limited6,7 and since no data are available on the pH of the endo/lysosomal compartment in trichomonads, we attempted (1) to determine the pH of the cytoplasm and the lysosome-like organelles of T. foetus, (2) to monitor pH changes in these organelles in trichomonads treated with agents inhibiting endo/lysosomal acidification, and (3) to investigate whether a pH increase in the lysosomal-like organelles influences the iron uptake from lactoferrin by T. foetus.