A Protein Aggregation Based Test for Screening of the Agents Affecting Thermostability of Proteins

To search for agents affecting thermal stability of proteins, a test based on the registration of protein aggregation in the regime of heating with a constant rate was used. The initial parts of the dependences of the light scattering intensity (I) on temperature (T) were analyzed using the following empiric equation: I = Kagg(T−T0)2, where Kagg is the parameter characterizing the initial rate of aggregation and T0 is a temperature at which the initial increase in the light scattering intensity is registered. The aggregation data are interpreted in the frame of the model assuming the formation of the start aggregates at the initial stages of the aggregation process. Parameter T0 corresponds to the moment of the origination of the start aggregates. The applicability of the proposed approach was demonstrated on the examples of thermal aggregation of glycogen phosphorylase b from rabbit skeletal muscles and bovine liver glutamate dehydrogenase studied in the presence of agents of different chemical nature. The elaborated approach to the study of protein aggregation may be used for rapid identification of small molecules that interact with protein targets

Extrinsic Fluorescent Dyes as Tools for Protein Characterization

Noncovalent, extrinsic fluorescent dyes are applied in various fields of protein analysis, e.g. to characterize folding intermediates, measure surface hydrophobicity, and detect aggregation or fibrillation. The main underlying mechanisms, which explain the fluorescence properties of many extrinsic dyes, are solvent relaxation processes and (twisted) intramolecular charge transfer reactions, which are affected by the environment and by interactions of the dyes with proteins. In recent time, the use of extrinsic fluorescent dyes such as ANS, Bis-ANS, Nile Red, Thioflavin T and others has increased, because of their versatility, sensitivity and suitability for high-throughput screening. The intention of this review is to give an overview of available extrinsic dyes, explain their spectral properties, and show illustrative examples of their various applications in protein characterization

The feeding tube of cyst nematodes: characterisation of protein exclusion

Plant parasitic nematodes comprise several groups; the most economically damaging of these are the sedentary endoparasites. Sedentary endoparasitic nematodes are obligate biotrophs and modify host root tissue, using a suite of effector proteins, to create a feeding site that is their sole source of nutrition. They feed by withdrawing host cell assimilate from the feeding site though a structure known as the feeding tube. The function, composition and molecular characteristics of feeding tubes are poorly characterised. It is hypothesised that the feeding tube facilitates uptake of host cell assimilate by acting as a molecular sieve. Several studies, using molecular mass as the sole indicator of protein size, have given contradictory results about the exclusion limits of the cyst nematode feeding tube. In this study we propose a method to predict protein size, based on protein database coordinates in silico. We tested the validity of these predictions using travelling wave ion mobility spectrometry--mass spectrometry, where predictions and measured values were within approximately 6%. We used the predictions, coupled with mass spectrometry, analytical ultracentrifugation and protein electrophoresis, to resolve previous conflicts and define the exclusion characteristics of the cyst nematode feeding tube. Heterogeneity was tested in the liquid, solid and gas phase to provide a comprehensive evaluation of three proteins of particular interest to feeding tube size exclusion, GFP, mRFP and Dual PI. The data and procedures described here could be applied to the design of plant expressed defence compounds intended for uptake into cyst nematodes. We also highlight the need to assess protein heterogeneity when creating novel fusion proteins

Single-epoch precise positioning using Modified Ambiguity Function Approach

Single-epoch positioning is a great challenge in recent research related to GNSS data processing. The Modified Ambiguity Function Approach (MAFA) method can be applied to perform this task. This method does not contain a stage of ambiguity resolution. However the final results take into account their integer nature. The functional model of the adjustment problem contains the conditions ensuring the integer nature of the ambiguities. A prerequisite for obtaining the correct solution is a mechanism ensuring appropriate convergence of the computational process. One of such mechanisms is a cascade adjustment, applying the linear combinations of the L1 and L2 signals with the integer coefficients and various wavelengths. Another method of increasing the efficiency of the MAFA method is based on the application of the integer de-correlation matrix to transform observation equations into equivalent, but better conditioned, observation equations. The next technique of improving the MAFA method is search procedure. This technique together with the de-correlation procedure allows to reduce the number of stages of the cascade adjustment and to obtain correct solution even in the case when a priori position is a few meters away from the actual position. This paper presents some problems related to search procedure. The results of single-epoch positioning using improved MAFA method are presented

Proposal for new strategy in precise positioning

In this paper a new approach for GNSS carrier-phase data processing is presented. This approach is based on some properties of Amtoiguity Function Method. New algorithm ensures the condition of integer ambiguities without necessity of cornputing it explicitly. The condition of "integerity" of the ambiguities is ensured through inserting condition eouations in the functional model of adjustment problem. An appropriate, differentiable function for the condition equations is proposed. Some numerical problems connected with new approach were resolved using variable linear combinations of GNSS signals in cascade adjustment algorithm

Testowanie wybranych serwisów automatycznego pozycjonowania w trybie postprocessingu

GPS data post-processing is time consuming and sometimes difficult task, that must be performed after each static survey. To obtain good coordinates, one must perform baseline processing and adjustment of GPS vectors. This requires both time and dedicated software. To speed up the process and save some money, surveyors may use automated, on-line GPS data processing systems. In this paper, authors compare results obtained from three automatic on-line GPS processing systems (Polish ASG-Eupos, Australian AUSPOS and American APPS) with respect to accuracy, availability and performance.Opracowanie obserwacji GPS w precyzyjnym pozycjonowaniu jest zadaniem złożonym i czasochłonnym. Musi być przeprowadzone po każdym pomiarze statycznym. Uzyskanie poprawnych współrzędnych wyznaczanego punktu jest możliwe po wyznaczeniu składowych wektorów GPS i wyrównaniu sieci tych wektorów. Zadanie to jest czasochłonne i wymaga odpowiedniego oprogramowania. Aby zaoszczędzić czas i pieniądze, geodeci mogą skorzystać z bezpłatnych serwisów opracowania obserwacji GPS.W artykule autorzy porównują wyniki uzyskane z trzech internetowych serwisów automatycznego opracowania obserwacji GPS (polskiego ASG-EUPOS, australijskiego AUSPOS i amerykańskiego APPS) pod względem ich dokładności, dostępności i działania

Numeric approach of estimation of integer value of phase's measurements

W artykule przedstawiony opracowany przez autorów sposób poszukiwania całkowitych wartości nieoznaczoności pomiaru fazowego. Sposób ten jest pewną numeryczną techniką poszukiwania optymalnego rozwiązania w teorii estymacji wartości całkowitych metodą najmniejszych kwadratów (theory of integer least squares). Zaprezentowano podstawy teoretyczne oraz przykłady numeryczne ilustrujące działanie metody.The self developed by authors approach of integer value of ambiguity search for phase’s measurements is presented in the paper. This approach is one of the numeric techniques of optimal solution search in theory of integer least squares. Theoretical bases as well as numeric examples illustrating of method are presented

Influence of pseudolite observations on GPS network adjustment

W artykule zaprezentowano wyniki wyrównania sieci GPS w trudnych warunkach pomiarowych. Sieć została wyrównana dwukrotnie - z oraz bez dołączonego pseudosatelity. Obliczenia zostały wykonane przy wykorzystaniu autorskiego oprogramowania umożliwiającego obliczenie wektora na podstawie obserwacji GPS i obserwacji od pseudosatelity. Wpływ dołączenia pseudosatelity na wyrównanie sieci określony został na podstawie porównania wyników wyrównania sieci GPS bez utrudnień, GPS z utrudnieniami oraz GPS+PL z utrudnieniami.This paper presents results of GPS network adjustment in difficult survey environment. Network was adjusted twice - with and without pseudolite observation. Calculations were made with authors own software for GPS and pseudolite data processing. The influence of pseudolite observation on GPS network adjustment was evaluated from differences between GPS only survey with no obstructions and survey with obstructions with and without pseudolite

Mapa wartości gruntów jako źródło informacji o lokalnym rynku nieruchomości

The objective of this study is to present the principles and methodology of drawing up a land value map, which consists of economic layers, such as a layer of transaction price monitoring, layer of purchaser preferences, layer of uniform value zones. While drawing up the land value maps, special attention was paid to the spatial analysis of the factors which determine the prices and value of a real estate property. Such a study results in drawing up a map which consists of a layer of transaction price monitoring, a layer of purchaser preferences and a layer of uniform value zonesCelem niniejszego studium jest prezentacja zasad i metodologii sporządzania mapy wartości gruntów, która zawiera warstwy ekonomiczne, takie jak: warstwa obserwacji cen transakcyjnych, warstwa preferencji nabywców, warstwa stref jednorodnych wartości. Podczas sporządzania map wartości szczególną wagę przywiązano do analizy przestrzennej czynników kształtujących ceny i wartość nieruchomości. Efektem badań jest opracowanie mapy wartości gruntów składającej się z warstwy monitoringu cen transakcyjnych, warstwy preferencji nabywców oraz warstwy stref jednorodnych wartośc