Flavin uptake and metabolism in Listeria monocytogenes and FMN riboswitches as targets for riboflavin analogs

The riboflavin analog roseoflavin – an antibiotic produced by the bacteria Streptomyces davawensis and Streptomyces cinnabarinus, and the key intermediate of the roseoflavin biosynthesis, 8-demthyl-8-amino riboflavin which is an antibiotic as well, are both known to have a growth inhibiting effect on the human pathogen Listeria monocytogens. The adverse effect of roseoflavin on L. monocytogenes has been proposed to be a result of its interaction with the FMN riboswitch Rli96, regulating expression of the riboflavin transporter gene lmo1945. Whether flavin analogs, such as roseoflavin and 8-demethyl-8-amino riboflavin, are assimilated by L. monocytogenes through the riboflavin transporter protein Lmo1945 has not yet been known. In addition, the conversion of flavin analogs into cofactor analogs by flavokinase/FAD synthetase enzymes from L. monocytogenes has not been investigated. The functional analysis of the effect of the cofactor analogs on the FMN riboswitch Rli96 could help to elucidate how flavin analogs affect riboflavin auxotrophic bacteria, including L. monocytogenes. Through heterologous expression of Lmo1945 in a riboflavin transporter deficient Bacillus subtilis strain, the role of Lmo1945 in the uptake of riboflavin and roseoflavin was confirmed. Two enzymes, catalyzing the conversion of riboflavin into the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) have been identified by sequence analysis. The bifunctional flavokinase/FAD synthetase Lmo1329 and the unique monofunctional FAD synthetase Lmo0728 were purified and kinetically characterized. Additionally, their involvement in the generation of the cofactor analogs roseoflavin mononucleotide (RoFMN), 8-demethyl-8-amino riboflavin mononucleotide (AFMN), roseoflavin adenine dinucleotide (RoFAD) and 8-demethyl-8-amino riboflavin adenine dinucleotide (AFAD) were shown in vitro. Notably, the bifunctional enzyme Lmo1329 did not convert the roseoflavin derived cofactor RoFMN into RoFAD. In vivo reporter gene assays and in vitro transcription/translation experiments showed that the FMN riboswitch Rli96, and consequently the expression of the riboflavin transporter gene lmo1945, is negatively affected by FMN and RoFMN but not by AFMN. With the FMN riboswitch Rli96, the riboflavin transporter Lmo1945, the bifunctional flavokinase/FAD synthetase Lmo1329 and the monofunctional FAD synthetase Lmo0728, the key mechanisms of riboflavin uptake and metabolism in L. monocytogenes were identified and characterized. Particularly, the FAD synthetase Lmo0728 is the first monofunctional FAD synthetase that has been described in bacteria. As a second part of this thesis a novel reporter system for in vivo studies of translational riboswitches in Streptomyces species was evaluated. However, the system proved to not be suitable for the desired application, i.e. the confirmation of previously obtained in vitro data. Several attempts to adapt and optimize the system failed which turned out to be due to the complexity of the natural expression platform in streptomycetes

Fish community composition in small lakes: The impact of lake genesis and fisheries management

Gravel pit lakes are common across Europe. These novel ecosystems serve as model systems to study human‐induced and natural colonisation of isolated lakes by fish. Fisheries‐management activities can quickly spread species over large distances, possibly homogenising fish communities across ecosystems, while fostering local fish diversity. Our objective was to evaluate the effects of lake genesis (gravel pit lakes < 100 years old vs. natural lakes of glacial genesis ~10,000 years old) and fisheries management (fish stocking activities present vs. absent) on the fish community in small lakes, while controlling for key environmental variables known to affect lake fish communities. We sampled fish communities by electrofishing and multimesh gillnetting in 47 isolated lakes managed for fisheries, and 19 unmanaged and isolated lakes of both natural and artificial origin in northern Germany. Unmanaged lakes were used as reference to assess fisheries‐management impacts in small natural and artificial lakes. We caught 178,506 fish from 30 species and found that the accumulation of native lake fish species in lakes was associated with fisheries management, which increased local species richness (α‐diversity) and number of predatory species, and reduced among‐lake variation in fish community composition (β‐diversity; i.e., homogenisation). The homogenisation‐effect associated with fisheries happened with introduced native fish species, whereas non‐native species were rarely detected. In unmanaged gravel pit lakes, the littoral fish community composition was substantially different to the communities present in both types of managed lakes and unmanaged natural lakes. Therefore, the relatively young unmanaged gravel pit lakes revealed evidence of ongoing, stochastic colonisation processes that resulted in comparatively species‐poor fish communities. We concluded that fisheries management by anglers speeds up the colonisation of gravel pit lakes with native fish species in the study area. For planning initial fish introductions in newly created gravel pit lakes, it is recommended that fish communities from ecologically similar natural lakes within the same geographical region are used as references to maintain the biotic integrity of newly created fish communities.This work was jointly supported by the German Federal Ministry of Education and Research (BMBF) and the German Federal Agency for Nature Conservation (BfN) with funds granted by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU; grant number: 16LC1320A).Peer Reviewe

Research of the relationship between the economic macroindicators of singleindustry city and aggregated indicators of small business

The report describes the research of dependencies between socio-economic macroindicators of the monogorod Yurga and the financial and economic indicators of small enterprises

Проект пункта технического обслуживания и диагностики автомобилей в условиях ООО «Автомотив Томск»

В данной выпускной квалифицированной работе подведены итоги работы по проектированию пункта технического обслуживания и диагностирования легковых автомобилей компании "Автомотив Томск" в г. Юрга. Выполнен анализ условий сервисных работ, предполагаемых охраной труда, рассмотрены нормы условий труда. Произведен расчет экономической эффективности от предполагаемой работы данного пункта технического обслуживания и диагностирования. В конструкторской части дипломного проекта спроектирован стенд для испытания и диагностики генераторов.In this graduate qualified work the results of work on the design of a point of maintenance and diagnostics of passenger cars of Avtomotiv Tomsk company in Yurga are summed up. The analysis of the conditions of service work assumed by labor protection is carried out, the norms of working conditions are considered. The calculation of economic efficiency from the proposed operation of this point of technical maintenance and diagnosis. In the design part of the diploma project, a stand was designed for testing and diagnostics of generators

Деловая карьера и ее развитие в Государственном профессиональном образовательном учреждении "Яшкинский техникум технологий и механизации" (пгт. Яшкино)

В современной России наблюдается разбалансированность рынка педагогического труда. Система образования не испытывает количественной нехватки преподавателей, но существуют трудности с удержанием молодых преподавателей и развитием уже работающих опытных специалистов. Цель работы – выявить особенности карьеры в образовательном учреждении современной России.Объект исследования – система управления деловой карьерой в организации.In modern Russia there is an imbalance of the market of pedagogical work. The education system does not have a quantitative shortage of teachers, but there are difficulties in retaining young teachers and developing experienced professionals who are already working. The purpose of the work is to identify the features of a career in an educational institution of modern Russia.The object of research is the system of business career management in the organization