Structural and biophysical studies of new L-asparaginase variants : lessons from random mutagenesis of the prototypic Escherichia coli Ntn-amido­hydrolase

This work reports the results of random mutagenesis of the Escherichia coli class 2 l-asparaginase EcAIII belonging to the Ntn-hydrolase family. New variants of EcAIII were studied using structural, biophysical and bioinformatic methods. Activity tests revealed that the l-asparaginase activity is abolished in all analyzed mutants with the absence of Arg207, but some of them retained the ability to undergo the autoproteolytic maturation process. The results of spectroscopic studies and the determined crystal structures showed that the EcAIII fold is flexible enough to accept different types of mutations; however, these mutations may have a diverse impact on the thermal stability of the protein. The conclusions from the experiments are grouped into six lessons focused on (i) the adaptation of the EcAIII fold to new substitutions, (ii) the role of Arg207 in EcAIII activity, (iii) a network of residues necessary for autoprocessing, (iv) the complexity of the autoprocessing reaction, (v) the conformational changes observed in enzymatically inactive variants and (vi) the cooperativity of the EcAIII dimer subunits. Additionally, the structural requirements (pre-maturation checkpoints) that are necessary for the initiation of the autocleavage of Ntn-hydrolases have been classified. The findings reported in this work provide useful hints that should be considered before planning enzyme-engineering experiments aimed at the design of proteins for therapeutic applications. This is especially important for l-asparaginases that can be utilized in leukemia therapy, as alternative therapeutics are urgently needed to circumvent the severe side effects associated with the currently used enzymes

Carbon dioxide emission from diesel engine vehicles in intermodal transport

Currently, many logistics operators operate in both domestic and foreign markets using various forms of transport organization. Choosing a corresponding technology and appropriate form of transport has an influence not only delivery time and costs, but also has an impact on the environment as a whole. There is a plethora of public research available in global literature discussing various ways of exploiting transport. On the other hand, there is a lack of complex studies detailing carbon emissions coming from transport activity. Specifically, where a theory of organic fuel combustion in the form of a chemical reaction with oxygen is considered. To fill this gap, we offer an innovative Emission Model of Industrial Sources (EMIS) method. This method makes it possible to determine the amount of CO2 emitted into the atmosphere during various transport methods. It also enables us to estimate, in terms of CO2 output, a threshold where transport of containers via combined mode becomes more favourable for the environment, than road transport. We ran a simulation of our algorithm to create boundary conditions. This let us prepare a regression function of CO2 emission, for intermodal and road transport as a function of various transport distances. The simulation results suggest that our approach may be used by supervisory institutions, which are responsible further developing and utilizing combined transport

A Refined Model for Carbon Footprint Estimation in Electric Railway Transport

There is a plethora of methods in the global literature that can be used to measure CO2 emissions from electrified transport. But are these methods reliable, and do they offer us a true view of how much exactly of this greenhouse gas is being produced by electric rail transport? We answer this question by proposing an improved CO2 emission estimation model based on cargo transport. Unlike other works, our studies include four crucial steps: (1) estimation of energy consumption in electrified rail cargo transport; (2) estimation of energy losses in the railway traction system and high voltage transmission lines; (3) CO2 emission estimation in traditional powerhouses; and (4) determination of the intensity of the CO2 emissions from electrified rail cargo transport. Based on our method, we concluded that the intensity of CO2 depends not only on the type of fossil fuel used for energy production but also on the parameters of the cargo train, such as its length and weight or the total number of wagon axles (which depend on wagon type). The achieved intensity of CO2 emissions in electrified rail cargo transport slightly varies from those reported in the global literature. Among the most important reasons responsible for this are the conditions under which these tests were conducted. Nevertheless, our results shed new light on how CO2 should be measured. We proved that the decarbonization of electrified rail cargo transport will never be possible without infrastructure modernization. In addition, based on a case study, we also delivered knowledge on how to reduce the environmental impact of electrified rail cargo transport

The perspectives of ecotourism development in Poland

Ekoturystyka jest mało popularną formą turystyki wiejskiej. Jak wskazują wyniki badań, tylko w przypadku 7% respondentów jest to wykorzystywana forma wypoczynku, a ponad 52% w ogóle o niej nie słyszało. W opinii badanych właścicieli gospodarstw ekoturystyce potrzebne jest wsparcie polityki regionalnej i intensywna promocja, pozwalająca na dotarcie do świadomości potencjalnych turystów.Ecotourism is a little popular form of village tourism. The results of the research show that only 7% of respondents use this form of spending free time while over 52% of them have never heard of it. According to the opinion of the surveyed ecotourism farms owners, ecotourism needs the support of regional policy and also intensive promotion which will enable to reach the awareness of potential tourists

The condition and the directions of changes in agricultural production in podlaskie voivodship

Opracowanie stanowi próbę prognozowania zmian w produkcji rolniczej w województwie podlaskim. Informacje o charakterze prognostycznym poparte są wynikami badań wielu autorów z zakresu zmian w strukturze użytkowania ziemi, produkcji roślinnej i zwierzęcej oraz skutków działalności rolniczej na przestrzeni ostatnich lat.This study is an attempt to forecast changes in agricultural production in Podlaskie Voivodship. The forecasting information is supported by the research results concerning changes in the structure of land use, plant and animal production as well as the effects of agricultural activity over the last years carried out by many scientists

A Successful Resection of Two Giant Mediastinal Neurogenic Tumors

We reported two cases of the giant mediastinal neurogenic tumors. Patients were women in middle age. In both cases the chest X-ray and CT (computed tomography) demonstrated the huge mass in a pleural cavity without intraspinal invasion. Radical procedures with removal of the giant tumors were performed. The postoperative treatment course was uneventful. The pathology showed schwannoma and neurofibroma. The follow up examination (6-24 months) showed no recurrence of the disease

Sequence determination and analysis of S-adenosyl-L-homocysteine hydrolase from yellow lupine (Lupinus luteus).

The coding sequences of two S-adenosyl-L-homocysteine hydrolases (SAHases) were identified in yellow lupine by screenig of a cDNA library. One of them, corresponding to the complete protein, was sequenced and compared with 52 other SAHase sequences. Phylogenetic analysis of these proteins identified three groups of the enzymes. Group A comprises only bacterial sequences. Group B is subdivided into two subgroups, one of which (B1) is formed by animal sequences. Subgroup B2 consist of two distinct clusters, B2a and B2b. Cluster B2b comprises all known plant sequences, including the yellow lupine enzyme, which are distinguished by a 50-residue insert. Group C is heterogeneous and contains SAHases from Archaea as well as a new class of animal enzymes, distinctly different from those in group B1

Complications after treating esophageal strictures with prostheses and stents – 20 years’ experience

Introduction : Over 80% of patients with esophageal cancer are qualified only for palliative treatment. The main goal of the therapy is to eliminate symptoms of dysphagia. Aim: To analyze complications after insertion of prostheses and stents in patients with inoperable cancer of the esophagus/cardia. Material and methods : From 1996 to 2015 prostheses of the esophagus were implanted in 1309 patients. In the strictures of the lower part of the esophagus, Barbin-Mousseau prostheses (102 cases) and Häring prostheses (324 cases) were placed. In the strictures of the upper and middle part of the esophagus, Wilson-Cook prostheses (65 cases) and Sumi prostheses (51 cases) were implanted using rigid oesophagoscopy. Since 2001, 867 esophageal stents have been implanted. Results: Complications occurred in 146 (11%) patients, including 7 (0.6%) cases of death. The most common complication was the recurrence of swallowing disorders (74 patients). In 51 patients, tumor overgrowth over the stent/prosthesis was responsible for that symptom, and in 23 patients its clogging. A fistula (22 cases) and the passage of the prosthesis/stent (25 cases) were the second most common group of complications. Compression of the trachea, bleeding, and dehiscence of wounds occurred in a total of 18 patients. Complications were mostly treated through the repositioning of the prosthesis/stent or the insertion of an additional one. Conclusions : The most common complications after esophageal prosthetics are the recurrence of dysphagia, a fistula and the displacement of the prosthesis/stent. The basic treatment of complications is the repositioning or insertion of an additional prosthesis

The Effect of Vacuum Forming on the Quality of Refractory Materials

Various designs of furnaces for melting alloys are used in the foundry industry. Regardless of their design, they have one common detail, which is the lining of their interiors with refractory materials. This component in the design of a metal-melting furnace has a very important task—to protect the rest of the furnace assemblies from thermal and mechanical damage. Continuous technical progress and the quality requirements of casting production produce increasingly higher demands for refractory materials in connection with their development as well. The article presents the results of an innovative method of vibratory compaction of refractory material (high-alumina aluminosilicate) using reduced pressure. The analysis presents a comparative study of two methods used for forming refractory materials, i.e., the application of the mentioned innovative method and the classical (standard) method of compaction by vibration only. The effects of the introduced modification in the manufacture of ceramic shapes were evaluated by means of the material’s resistance to thermal shock, linear expansion, and dimensional change due to firing, apparent density, open porosity, and apparent specific gravity, determination of total pore volume and pore size distribution by mercury porosimetry, and slag resistance. The tests performed indicate that the procedure of lowering the pressure during the vibratory compaction of the refractory material creates a more homogeneous structure with a smaller number and size of pores. This makes it possible to improve most of the parameters that determine the quality of the refractories used for the linings of the foundry furnace

Aktualne zasady postępowania w przypadku wrodzonej przepukliny przeponowej

The treatment of congenital diaphragmatic hernia (CDH) still represents a challenge, even for the specialised multidisciplinary teams in centres that provide treatment for CDH. Despite significant progress in the fields of pathophysiology, prenatal diagnosis, surgical techniques and intensive care, CDH is a disease still burdened with a high mortality. Due to the paucity of randomised studies, there are no standard guidelines for treatment. The present review looks at existing diagnostic and therapeutic principles based on the available literature.The treatment of congenital diaphragmatic hernia (CDH) still represents a challenge, even for the specialised multidisciplinary teams in centres that provide treatment for CDH. Despite significant progress in the fields of pathophysiology, prenatal diagnosis, surgical techniques and intensive care, CDH is a disease still burdened with a high mortality. Due to the paucity of randomised studies, there are no standard guidelines for treatment. The present review looks at existing diagnostic and therapeutic principles based on the available literature