A study on L-threonine and L-serine uptake in Escherichia coli K-12

In the current study, we report the identification and characterization of the yifK gene product as a novel amino acid carrier in E. coli K-12 cells. Both phenotypic and biochemical analyses showed that YifK acts as a permease specific to L-threonine and, to a lesser extent, L-serine. An assay of the effect of uncouplers and composition of the reaction medium on the transport activity indicates that YifK utilizes a proton motive force to energize substrate uptake. To identify the remaining threonine carriers, we screened a genomic library prepared from the yifK-mutant strain and found that brnQ acts as a multicopy suppressor of the threonine transport defect caused by yifK disruption. Our results indicate that BrnQ is directly involved in threonine uptake as a low-affinity but high-flux transporter, which forms the main entry point when the threonine concentration in the external environment reaches a toxic level. By abolishing YifK and BrnQ activity, we unmasked and quantified the threonine transport activity of the LIV-I branched chain amino acid transport system and demonstrated that LIV-I contributes significantly to total threonine uptake. However, this contribution is likely smaller than that of YifK. We also observed the serine transport activity of LIV-I, which was much lower compared with that of the dedicated SdaC carrier, indicating that LIV-I plays a minor role in the serine uptake. Overall, these findings allow us to propose a comprehensive model of the threonine/serine uptakesubsystem in E. coli cells

Интернализация рекомбинантной имиглюцеразы в перитонеальные макрофаги мыши и фибробласты мыши линии L929

Enzyme replacement therapy (ERT) is one of the most efficient treatments for lysosomal storage diseases. Type 1 Gaucher disease is caused by β-glucocerebrosidase enzyme deficiency, which may be compensated for by intravenous infusions of imiglucerase—a recombinant enzyme. Imiglucerase targets macrophages and enters these cells via interaction with mannose receptors on the cell membrane. Characterisation of internalization of enzymes by target cells is important in the context of the development of new medicines and production of existing ERT medicines. The peritoneal and alveolar macrophages, as well as macrophages of the spleen of small laboratory animals (rats and mice) are widely used in such studies. However, isolation of cells from animal sources raises ethical issues, and therefore continuous mammalian cell lines may offer an attractive alternative. The aim of the study: to conduct comparative studies on the internalization of recombinant imiglucerase into mouse peritoneal macrophages and L929 mouse fibroblasts. Materials and methods: CerezymeR batches 7HV0913, C6214H05, 7HV0888 (Genzyme Ltd., UK); Glurazim batches 020416, 011117, 021117 (LLC “IBC “Generium”, Russia). We used peritoneal macrophages obtained from BALB/c mice and L929 mouse fibroblasts. The cells were cultured in DMEM/F12 complete growth medium with 10% fetal bovine serum. The activity of imiglucerase internalized into the cells was evaluated spectrophotometrically by hydrolysis of the artificial substrate—4-methylumbelliferyl-β-Dglucopyranoside. Results: the study compared internalization of recombinant imiglucerase (the active ingredient of CerezymeR and Glurazim) by mouse peritoneal macrophages and L929 mouse fibroblasts. It was demonstrated that the medicines activity in the lysates of peritoneal macrophages is comparable with that in the lysates of L929 mouse fibroblasts. Regardless of the model system, the activity of Glurazim stayed within the acceptable range (80–125%) established for biosimilar products. Conclusions: the experiments proved that L929 mouse fibroblasts could be recommended for assessment of internalization of recombinant imiglucerase.Фермент-заместительная терапия (ФЗТ) является одной из самых действенных при лечении болезней лизосомального накопления. Болезнь Гоше первого типа характеризуется недостатком нативного фермента β-глюкоцереброзидазы, который возмещают внутривенными инфузиями рекомбинантного фермента (имиглюцераза). Клетками-мишенями имиглюцеразы являются макрофаги, в которые фермент проникает посредством взаимодействия с рецепторами маннозы на клеточной мембране. Оценка интернализации ферментов клетками-мишенями представляет интерес при разработке новых и воспроизведении существующих препаратов для ФЗТ. Для этих исследований широко применяются перитонеальные и альвеолярные макрофаги, макрофаги селезенки мелких лабораторных животных (крыс и мышей). Однако получение таких клеток затрагивает этические вопросы использования лабораторных животных. Альтернативой являются перевиваемые клеточные линии млекопитающих. Цель работы: провести сравнительные исследования интернализации рекомбинантной имиглюцеразы в перитонеальные макрофаги мыши и фибробласты мыши линии L929. Материалы и методы: Церезим®, серии 7HV0913, C6214H05, 7HV0888 (Джензайм Лтд., Великобритания); Глуразим, серии 020416, 011117, 021117 (ООО «МБЦ «Генериум», Россия). В работе использовали перитонеальные макрофаги, полученные от мышей линии BALB/c, и фибробласты мыши линии L929. Клетки культивировали в полной ростовой среде ДМЕМ/Ф12 c добавлением 10% сыворотки плода крупного рогатого скота. Активность имиглюцеразы, проникшей в клетки, оценивали спектрофотометрически по гидролизу искусственного субстрата 4-метилумбеллиферил-β-D-глюкопиранозида. Результаты: представлены данные сравнительной оценки интернализации рекомбинантной имиглюцеразы, действующего вещества препаратов Церезим® и Глуразим, перитонеальными макрофагами мыши и клетками фибробластов мыши линии L929. Показано, что активность препаратов в лизатах перитонеальных макрофагов сопоставима с их активностью в лизатах клеток фибробластов мыши линии L929, при этом активность разработанного препарата Глуразим независимо от типа клеток, была в границах допустимого диапазона (80–125%), установленного для биоподобных препаратов. Выводы: экспериментально доказано, что фибробласты мыши линии L929 могут быть рекомендованы для оценки интернализации рекомбинантной имиглюцеразы

Persistent Hyperdopaminergia Decreases the Peak Frequency of Hippocampal Theta Oscillations during Quiet Waking and REM Sleep

Long-term changes in dopaminergic signaling are thought to underlie the pathophysiology of a number of psychiatric disorders. Several conditions are associated with cognitive deficits such as disturbances in attention processes and learning and memory, suggesting that persistent changes in dopaminergic signaling may alter neural mechanisms underlying these processes. Dopamine transporter knockout (DAT-KO) mice exhibit a persistent five-fold increase in extracellular dopamine levels. Here, we demonstrate that DAT-KO mice display lower hippocampal theta oscillation frequencies during baseline periods of waking and rapid-eye movement sleep. These altered theta oscillations are not reversed via treatment with the antidopaminergic agent haloperidol. Thus, we propose that persistent hyperdopaminergia, together with secondary alterations in other neuromodulatory systems, results in lower frequency activity in neural systems responsible for various cognitive processes

Resting-State Quantitative Electroencephalography Reveals Increased Neurophysiologic Connectivity in Depression

Symptoms of Major Depressive Disorder (MDD) are hypothesized to arise from dysfunction in brain networks linking the limbic system and cortical regions. Alterations in brain functional cortical connectivity in resting-state networks have been detected with functional imaging techniques, but neurophysiologic connectivity measures have not been systematically examined. We used weighted network analysis to examine resting state functional connectivity as measured by quantitative electroencephalographic (qEEG) coherence in 121 unmedicated subjects with MDD and 37 healthy controls. Subjects with MDD had significantly higher overall coherence as compared to controls in the delta (0.5–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (12–20 Hz) frequency bands. The frontopolar region contained the greatest number of “hub nodes” (surface recording locations) with high connectivity. MDD subjects expressed higher theta and alpha coherence primarily in longer distance connections between frontopolar and temporal or parietooccipital regions, and higher beta coherence primarily in connections within and between electrodes overlying the dorsolateral prefrontal cortical (DLPFC) or temporal regions. Nearest centroid analysis indicated that MDD subjects were best characterized by six alpha band connections primarily involving the prefrontal region. The present findings indicate a loss of selectivity in resting functional connectivity in MDD. The overall greater coherence observed in depressed subjects establishes a new context for the interpretation of previous studies showing differences in frontal alpha power and synchrony between subjects with MDD and normal controls. These results can inform the development of qEEG state and trait biomarkers for MDD

МЕРЕЖЕВІ ТЕХНОЛОГІЇ НАВЧАННЯ МОВ

У роботі розглядаються технології навчання української мови в мережевій мовній лабораторії – комп’ютерному класі зі спеціальним програмним забезпеченням. Зроблено огляд сучасних програмних продуктів, які можна використовувати для управління навчальним процесом в мережі Intranet. Для управління навчальним процесом в даній роботі апробовано систему управління комп’ютерним класом HiClass. Запропоновано деякі педагогічні сценарії використання можливостей системи HiClass: індивідуальне виконання вправ з on-line-перевіркою, комбіновані схеми виконання аудиторних завдань; електронні диктанти. Описано систему комп’ютерного тестування, яка дозволяє здійснювати створення тестів і автоматизовану їх перевірку

EDUCATION IN THE ERA OF INFORMATION CHALLENGE

The article presents an analysis of changes in the basic orientations of the education system in the information age, in the context of dialogue of cultures and transdisciplinarity of scientific research. In these conditions education should be a continuous process, a way of life (activity) of each person, his self-education, self-creation. Therefore, the most important task of school is the development of students' ability to learn and form their need for self-education. To solve this problem it is necessary to create an innovative school, creative (dialogical) pedagogy, and a complex multifunctional educational environment. As one of the tools of creative pedagogy a pilot innovation project of a social science textbook for secondary school was offered at the School of Public Administration Lomonosov Moscow State University

Internalization of Recombinant Imiglucerase into Mouse Peritoneal Macrophages and L929 Mouse Fibroblasts

Enzyme replacement therapy (ERT) is one of the most efficient treatments for lysosomal storage diseases. Type 1 Gaucher disease is caused by β-glucocerebrosidase enzyme deficiency, which may be compensated for by intravenous infusions of imiglucerase—a recombinant enzyme. Imiglucerase targets macrophages and enters these cells via interaction with mannose receptors on the cell membrane. Characterisation of internalization of enzymes by target cells is important in the context of the development of new medicines and production of existing ERT medicines. The peritoneal and alveolar macrophages, as well as macrophages of the spleen of small laboratory animals (rats and mice) are widely used in such studies. However, isolation of cells from animal sources raises ethical issues, and therefore continuous mammalian cell lines may offer an attractive alternative. The aim of the study: to conduct comparative studies on the internalization of recombinant imiglucerase into mouse peritoneal macrophages and L929 mouse fibroblasts. Materials and methods: CerezymeR batches 7HV0913, C6214H05, 7HV0888 (Genzyme Ltd., UK); Glurazim batches 020416, 011117, 021117 (LLC “IBC “Generium”, Russia). We used peritoneal macrophages obtained from BALB/c mice and L929 mouse fibroblasts. The cells were cultured in DMEM/F12 complete growth medium with 10% fetal bovine serum. The activity of imiglucerase internalized into the cells was evaluated spectrophotometrically by hydrolysis of the artificial substrate—4-methylumbelliferyl-β-Dglucopyranoside. Results: the study compared internalization of recombinant imiglucerase (the active ingredient of CerezymeR and Glurazim) by mouse peritoneal macrophages and L929 mouse fibroblasts. It was demonstrated that the medicines activity in the lysates of peritoneal macrophages is comparable with that in the lysates of L929 mouse fibroblasts. Regardless of the model system, the activity of Glurazim stayed within the acceptable range (80–125%) established for biosimilar products. Conclusions: the experiments proved that L929 mouse fibroblasts could be recommended for assessment of internalization of recombinant imiglucerase

A study on L-threonine and L-serine uptake in Escherichia coli K-12

In the current study, we report the identification and characterization of the yifK gene product as a novel amino acid carrier in E. coli K-12 cells. Both phenotypic and biochemical analyses showed that YifK acts as a permease specific to L-threonine and, to a lesser extent, L-serine. An assay of the effect of uncouplers and composition of the reaction medium on the transport activity indicates that YifK utilizes a proton motive force to energize substrate uptake. To identify the remaining threonine carriers, we screened a genomic library prepared from the yifK-mutant strain and found that brnQ acts as a multicopy suppressor of the threonine transport defect caused by yifK disruption. Our results indicate that BrnQ is directly involved in threonine uptake as a low-affinity but high-flux transporter, which forms the main entry point when the threonine concentration in the external environment reaches a toxic level. By abolishing YifK and BrnQ activity, we unmasked and quantified the threonine transport activity of the LIV-I branched chain amino acid transport system and demonstrated that LIV-I contributes significantly to total threonine uptake. However, this contribution is likely smaller than that of YifK. We also observed the serine transport activity of LIV-I, which was much lower compared with that of the dedicated SdaC carrier, indicating that LIV-I plays a minor role in the serine uptake. Overall, these findings allow us to propose a comprehensive model of the threonine/serine uptake subsystem in E. coli cells