Functional Expression of the Heteromeric “Olfactory” Cyclic Nucleotide-Gated Channel in the Hippocampus: A Potential Effector of Synaptic Plasticity in Brain Neurons

Cyclic nucleotide-gated (cng) channels are important components of signaling systems mediating sensory transduction. In vertebrate photoreceptors, light activates a signaling cascade that causes a decrease in intracellular cGMP concentrations, closing retinal cng channels. Signal transduction in olfactory receptor neurons is believed to proceed via G-protein-mediated elevation of intracellular cAMP in response to odorant binding by 7-helix receptors. cAMP opens the olfactory cng channel, which is highly permeable to Ca^(2+). Here we demonstrate by in situ hybridization and immunohistochemistry with subunit-specific antibodies that both subunits of the heteromeric rat olfactory cng channel are also widely expressed in the brain. Expression of the retinal rod cng channel, however, can be detected only in the eye. In the adult hippocampus, the olfactory cng channel is expressed on cell bodies and processes of CA1 and CA3 neurons. In cultured embryonic hippocampal neurons, the channel is localized to a subset of growth cones and processes. We recorded conductances with the electrophysiological characteristics of the heteromeric olfactory cng channel in excised inside-out patches from these cultured neurons. We also show that Ca^(2+) influx into hippocampal neurons in response to cyclic nucleotide elevation can be detected using fura-2 imaging. Cyclic nucleotide elevation has been implicated in several mechanisms of synaptic plasticity in the hippocampus, and these mechanisms also require elevation of intracellular Ca^(2+). Our results suggest that the “olfactory” cng channel could regulate synaptic efficacy in brain neurons by modulating Ca^(2+) levels in response to changes in cyclic nucleotide concentrations

A critical role of tropomyosins in TGF-beta regulation of the actin cytoskeleton and cell motility in epithelial cells

We have investigated transforming growth factor beta (TGF-beta)-mediated induction of actin stress fibers in normal and metastatic epithelial cells. We found that stress fiber formation requires de novo protein synthesis, p38Mapk and Smad signaling. We show that TGF-beta via Smad and p38Mapk up-regulates expression of actin-binding proteins including high-molecular-weight tropomyosins, alpha-actinin and calponin h2. We demonstrate that, among these proteins, tropomyosins are both necessary and sufficient for TGF-beta induction of stress fibers. Silencing of tropomyosins with short interfering RNAs (siRNAs) blocks stress fiber assembly, whereas ectopic expression of tropomyosins results in stress fibers. Ectopic-expression and siRNA experiments show that Smads mediate induction of tropomyosins and stress fibers. Interestingly, TGF-beta induction of stress fibers was not accompanied by changes in the levels of cofilin phosphorylation. TGF-beta induction of tropomyosins and stress fibers are significantly inhibited by Ras-ERK signaling in metastatic breast cancer cells. Inhibition of the Ras-ERK pathway restores TGF-beta induction of tropomyosins and stress fibers and thereby reduces cell motility. These results suggest that induction of tropomyosins and stress fibers play an essential role in TGF-beta control of cell motility, and the loss of this TGF-beta response is a critical step in the acquisition of metastatic phenotype by tumor cells

Parameters of loading equilibration in a tube cold pilger mill drive

On the basis of the variational approach and the Gauss-Seidel method there are proposed a technique and a mathematical model for determining the optimal parameters of dynamic load balancing systems on the crankshaft on the example of the cold rolling mill tube with reciprocating motion of an executive element in the form of a large mass working stand. The most compact scheme with the orthogonal motion of the executive element and the balancing load was chosen as the dynamic balance system. Variable parameters include dezaxial values, misalignment angle of cranks, weight of counterweight and balancing weight, lengths of connecting rods of executive and balancing mechanisms. For the existing series of sizes of cold rolling tube mill as the mass and speed of the rolling stand increase, the proportion of dynamic and technological components of the reduced load and respectively the kinematic scheme of the balancing mechanism changes. In this case, the structure of the loading and a set of variable parameters remain unchanged. Therefore, the proposed mathematical model of dynamic programming retains the universality of finding the minimum of maximum of the resulting load. © Published under licence by IOP Publishing Ltd

The Boechera Genus as a Resource for Apomixis Research

The genera Boechera (A. Löve et D. Löve) and Arabidopsis, the latter containing the model plant Arabidopsis thaliana, belong to the same clade within the Brassicaceae family. Boechera is the only among the more than 370 genera in the Brassicaceae where apomixis is well documented. Apomixis refers to the asexual reproduction through seed, and a better understanding of the underlying mechanisms has great potential for applications in agriculture. The Boechera genus currently includes 110 species (of which 38 are reported to be triploid and thus apomictic), which are distributed mostly in the North America. The apomictic lineages of Boechera occur at both the diploid and triploid level and show signs of a hybridogenic origin, resulting in a modification of their chromosome structure, as reflected by alloploidy, aneuploidy, substitutions of homeologous chromosomes, and the presence of aberrant chromosomes. In this review, we discuss the advantages of the Boechera genus to study apomixis, consider its modes of reproduction as well as the inheritance and possible mechanisms controlling apomixis. We also consider population genetic aspects and a possible role of hybridization at the origin of apomixis in Boechera. The molecular tools available to study Boechera, such as transformation techniques, laser capture microdissection, analysis of transcriptomes etc. are also discussed. We survey available genome assemblies of Boechera spp. and point out the challenges to assemble the highly heterozygous genomes of apomictic species. Due to these challenges, we argue for the application of an alternative reference-free method for the comparative analysis of such genomes, provide an overview of genomic sequencing data in the genus Boechera suitable for such analysis, and provide examples of its application

Mathematical Model of Speed Control System Induction Motor with the Purpose of Increasing its Service Life

В статье рассматривается замкнутая система регулирования частоты вращения асинхронного двигателя (АД), пропорционального регулятора и тиристорного преобразователя напряжения (ТПН). Разработана математическая модель регулирования частоты вращения АД, позволяющая снизить потери мощности в установившихся режимах и при допустимых параметрах переходных процессов для режимов холостого хода и малых нагрузок. Математическая модель АД с ТПН описывается в виде полиноминальных зависимостей от режимных параметров. Модель базируется на экспериментальных данных АД различной мощности. Разработана методика оценки эффективного использования электрической энергии в виде коэффициента мощности АД. Определен оптимизированный вариант формы регулировочной характеристики по критерию минимума затрат электрической энергии. Приведены экспериментальные и расчетные данные, даны практические рекомендации.The article deals with a closed system speed control of induction motor (IM), proportional controller and thyristor voltage converter (TVC). A mathematical model of regulation speed of IM, which reduces losses power in steady-state conditions and with permissible parameters of transients for idling and low load. The mathematical model of IM with TVC is described in the form polynomial dependencies on the regime parameters. The model is based on experimental data of IM of different power. Developed by methodology for assessing effective use electrical energy in the form of a power factor IM. An optimized form is defined by the criterion minimum electrical energy costs. Are presented experimental and calculated data are given practical recommendations

Особенностью течения тяжелых форм СOVID-19 является высокий уровень воспаления, требующий применения дополнительных диагностических технологий для уточнения вызывающей его причины

Subjects and methods. The retrospective study included 37 patients (n = 37) diagnosed with severe viral pneumonia (SARS-CoV2) who were treated in the intensive care unit of Pavlov First Saint Petersburg State Medical University. To assess the significance of PADM as a biomarker of bacterial infection, patients were divided into two groups: the group of patients with viral pneumonia without sepsis (n = 24) and the group of those who developed sepsis and septic shock complicating the course of the new coronavirus infection (n = 13). PADM was assessed as a criterion for the severity of the disease in the groups of deceased (n = 19) and survivors (n = 18). Data were statistically processed in the computer mathematics system R, version 3.6.2, the prognostic significance of PADM was assessed using linear regression.Results. The median PADM in the group without sepsis was higher than the reference value – 1.1 (0.5; 4.3) nmol/L, in patients with sepsis that complicated the course of viral pneumonia – 2.8 (1.1; 5.7) nmol/L (p = 0.0019). Significant differences were revealed between the baseline levels of PADM in patients with different outcomes: in the surviving group, the median was 0.99 (0.5; 3.14) nmol/L, and in the group of deceased – 2.70 (0.94; 5.86 ) nmol/L. In surviving patients, the changes in PADM levels had a linear distribution throughout the entire period of stay in the intensive care unit. In deceased patients, within 20 days before death, PADM tended to grow significantly and reached its maximum by the time of the outcome.Conclusion. The assessment of the PADM blood level can be used to clarify the addition of a bacterial infection in patients with pneumonia caused by the SARS-CoV2 virus. The study of changes in its level makes it possible to objectify the prediction of the course of COVID-19 – favorable or unfavorable. Data accumulation is required to clarify specific PADM values that predict the outcome in COVID-19 patients. Цель: изучить информационную значимость проадреномедуллина (ПАДМ) у пациентов с новой коронавирусной инфекцией COVID-19.Материалы и методы. В ретроспективное исследование включено 37 пациентов (n = 37) с подтвержденным диагнозом вирусной пневмонии (SARS-CoV2) тяжелого течения, проходивших лечение в отделении реанимации и интенсивной терапии ПСПбГМУ им. акад. И. П. Павлова. Для оценки значимости ПАДМ как биомаркера бактериальной инфекции пациентов разделили на две группы: с вирусной пневмонией без сепсиса (n = 24) и с развитием сепсиса и септического шока, осложнивших течение новой коронавирусной инфекции (n = 13). Оценку ПАДМ как критерия тяжести течения заболевания проводили в группах умерших (n = 19) и выживших (n = 18). Статистическую обработку данных выполняли в системе компьютерной математики R версии 3.6.2, оценку прогностической значимости ПАДМ ‒ с помощью линейной регрессии.Результаты. Медиана ПАДМ в группе без сепсиса была выше референсного значения ‒ 1,1 (0,5; 4,3) нмоль/л, у пациентов с сепсисом, осложнившим течение вирусной пневмонии, ‒ 2,8 (1,1; 5,7) нмоль/л (p = 0,0019). Выявлены значимые различия между исходными уровнями ПАДМ у больных с разным исходом: в группе выживших медиана составила 0,99 (0,5;3,14) нмоль/л, а в группе умерших ‒ 2,70 (0,94; 5,86) нмоль/л. У выживших пациентов динамика показателя имела линейное распределение в течение всего периода пребывания в отделении реанимации и интенсивной терапии. У умерших пациентов в течение 20 сут до летального исхода наблюдалась тенденция к значимому нарастанию показателя, который достигал максимума к моменту исхода.Заключение. Оценку уровня ПАДМ в крови можно использовать для уточнения факта присоединения бактериальной инфекции у пациентов с пневмонией, вызванной вирусом SARS-CoV2. Исследование его концентрации в динамике позволяет объективизировать представление о направленности течения COVID-19 – благоприятном или неблагоприятном. Для уточнения конкретных значений ПАДМ, позволяющих прогнозировать исход у пациентов с COVID-19, требуется накопление данных.

Intratumoral macrophages contribute to epithelial-mesenchymal transition in solid tumors

<p>Abstract</p> <p>Background</p> <p>Several stromal cell subtypes including macrophages contribute to tumor progression by inducing epithelial-mesenchymal transition (EMT) at the invasive front, a mechanism also linked to metastasis. Tumor associated macrophages (TAM) reside mainly at the invasive front but they also infiltrate tumors and in this process they mainly assume a tumor promoting phenotype. In this study, we asked if TAMs also regulate EMT intratumorally. We found that TAMs through TGF-β signaling and activation of the β-catenin pathway can induce EMT in intratumoral cancer cells.</p> <p>Methods</p> <p>We depleted macrophages in F9-teratocarcinoma bearing mice using clodronate-liposomes and analyzed the tumors for correlations between gene and protein expression of EMT-associated and macrophage markers. The functional relationship between TAMs and EMT was characterized <it>in vitro </it>in the murine F9 and mammary gland NMuMG cells, using a conditioned medium culture approach. The clinical relevance of our findings was evaluated on a tissue microarray cohort representing 491 patients with non-small cell lung cancer (NSCLC).</p> <p>Results</p> <p>Gene expression analysis of F9-teratocarcinomas revealed a positive correlation between TAM-densities and mesenchymal marker expression. Moreover, immunohistochemistry showed that TAMs cluster with EMT phenotype cells in the tumors. <it>In vitro</it>, long term exposure of F9-and NMuMG-cells to macrophage-conditioned medium led to decreased expression of the epithelial adhesion protein E-cadherin, activation of the EMT-mediating β-catenin pathway, increased expression of mesenchymal markers and an invasive phenotype. In a candidate based screen, macrophage-derived TGF-β was identified as the main inducer of this EMT-associated phenotype. Lastly, immunohistochemical analysis of NSCLC patient samples identified a positive correlation between intratumoral macrophage densities, EMT markers, intraepithelial TGF-β levels and tumor grade.</p> <p>Conclusions</p> <p>Data presented here identify a novel role for macrophages in EMT-promoted tumor progression. The observation that TAMs cluster with intra-epithelial fibroblastoid cells suggests that the role of macrophages in tumor-EMT extends beyond the invasive front. As macrophage infiltration and pronounced EMT tumor phenotype correlate with increased grade in NSCLC patients, we propose that TAMs also promote tumor progression by inducing EMT locally in tumors.</p