The M-band: the underestimated part of the sarcomere

The sarcomere is the basic unit of the myofibrils, which mediate skeletal and cardiac Muscle contraction. Two transverse structures, the Z-disc and the M-band, anchor the thin (actin and associated proteins) and thick (myosin and associated proteins) filaments to the elastic filament system composed of titin. A plethora of proteins are known to be integral or associated proteins of the Z-disc and its structural and signalling role in muscle is better understood, while the molecular constituents of the M-band and its function are less well defined. Evidence discussed here suggests that the M-band is important for managing force imbalances during active muscle contraction. Its molecular composition is fine-tuned, especially as far as the structural linkers encoded by members of the myomesin family are concerned and depends on the specific mechanical characteristics of each particular muscle fibre type. Muscle activity signals from the M-band to the nucleus and affects transcription of sarcomeric genes, especially via serum response factor (SRF). Due to its important role as shock absorber in contracting muscle, the M-band is also more and more recognised as a contributor to muscle disease. [Abstract copyright: Copyright © 2019. Published by Elsevier B.V.

Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution

Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system

FEATURES OF THE FORMATION OF PRODUCTIVITY AND ADAPTIVE REACTIONS IN LEGUMINOUS CROP VARIETIES WITH RECESSIVE ALLELES OF GENES

Researches were carried out on varieties, hybrids, isogenic lines and mutants of peas of various use developed from the beginning of the 1980s up to 2013. Experimental material was investigated under field conditions in the collection, hybridization and breeding nurseries as well as in the process of competitive variety testing in Orel Province. It is shown that one or several recessive alleles of the genes introduced into the genotypes of new varieties of grain, fodder and vegetable peas, blue lupin and soybean can influence the changees in a great number of morphological and physiological parameters determining plant growth, development and also characteristics in the system of yield formation. Reduction of leaf area in leafless pea varieties and lupin varietitts with limited branching is connected with the weakening of root system growth, which is caused by trophic interaction between these organs

Making Muscle Elastic: The Structural Basis of Myomesin Stretching

The muscle M-band protein myomesin comprises a 36-nm long filament made of repetitive immunoglobulin–helix modules that can stretch to 2.5-fold this length, demonstrating substantial molecular elasticity

Results of Monitoring over the West Nile Fever Pathogen in the Territory of the Russian Federation in 2017. Forecast of Epidemic Situation Development in Russia in 2018

In Europe, in the epidemic season 2017, the incidence of West Nile fever did not exceed the index of the previous season. In the US and Canada, there was an increase in the incidence of cases. West Nile fever morbidity rates in the Russian Federation and in separate constituent entities were below the average long-term index and had the lowest value for the period since 2008. 41.6 % of WNF cases were imported to Russia from the distant countries. Analysis of the monitoring results indicated the circulation of WNF virus markers in carriers of the pathogen in 6 constituent entities of the Russian Federation, and the presence of IgG antibodies in healthy population cohorts in 24 RF entities. According to molecular-genetic typing of WNF virus samples from mosquito Culex modestus from the Volgograd Region, WNF virus genotype II was established. Forecasting of epidemiological situation development for the year 2018 does not rule out the possibility of local increase in WNF incidence in certain regions of Russia

Факторы риска и математическая модель осложненного течения беременности на основании интегративного анализа

Objective: To identify additional  risk factors  of   complicated  pregnancy  and to  develop  a mathematical model for prognosing   the course  of gestation  using integrative  analysis.Materials  and  methods.  We  carried   out  a  prospective   parallel  group  study  of  240 women  with  low perinatal risk in the  first and second trimesters  of pregnancy.  To  study  the  psycho-emotional state  and personality characteristics of pregnant  women, we used the SF-36 questionnaire, Osgood’s Semantic differential,  G.  Eysenck’s   self-assessment  personality test  and  the  Big five questionnaire proposed   by R. McCrae  and P. Costa. To assess the impact  of the environment  on pregnancy,  a questionnaire “Degree of satisfaction  with the urban  environment”  composed  by   Yu.Kataeva was used.Results. We established  additional  criteria for  predicting  the  course  of gestation.  In  the  first  trimester they were restrictions of everyday functions due to painful manifestations  and signs of early toxicosis, poor health,  bad mood,  high levels of anxiety,  difficulty in being flexible in new life conditions  and a tendency to react  aggressively. In the second trimester they experienced  painful conditions,  mood swings, preferring seclusion to  relationships  and lack of satisfaction  with the  quality  of the  urban  environment.  During the interpretation of the  study  results  we identified  additional  prognostic  factors  of the  unfavorable  course of pregnancy,  which allow us to develop targeted programs  for medical and psychological  support  during pregnancy. Conclusion. We investigated  the  interrelations between  the  most  important factors  affecting  the  normal course  of pregnancy,  childbirth and the condition  of the newborn.  This study will allow us to predict  the course  of pregnancy  and elicit  additional  criteria to  form  groups  with  increased  obstetric and perinatal risks.  We  also  designed  a  mathematical model  for  prognosing  the  course  of  gestation  that  takes  into account  the identified additional  criteria.Цель работы: выявить дополнительные  факторы  риска  осложненного течения  беременности  и разработать  математическую  модель  прогнозирования течения  гестационного процесса  на основании комплексного  подхода.Материалы и  методы. Проведено   простое  проспективное  исследование   в  параллельных   группах 240 женщин низкой степени перинатального риска в I и II триместрах  беременности.  Для исследования психоэмоционального состояния и личностных особенностей  беременных женщин использовали опросник  «Качество  жизни»  SF-36, Семантический  дифференциал Ч. Осгуд, методику «Самооценка психических  состояний»  Г. Айзенка,  Пятифакторный личностный  опросник  (Big five) Р. МакКрае и П. Коста.  Для оценки влияния  окружающей  среды   использовали  анкету  изучения  степени  удовлетворенности городской  средой Ю.В. Катаевой.Результаты. Установлены  дополнительные   критерии  для  прогнозирования течения  гестационного процесса. Для I триместра такими факторами оказались:  наличие ограничений в выполнении повседневных ролевых функций  вследствие болезненных  проявлений  и признаков  раннего токсикоза, плохое самочувствие,  пониженное  настроение,  высокая  тревожность, трудность  к гибкому  поведению в новых  жизненных  условиях  и тенденция  к использованию  агрессивных  способов  реагирования. Для II триместра:  наличие ощущений болезненного состояния, склонность  к быстрой смене настроения,  предпочтение  уединения  близким  отношениям  и неудовлетворенность качеством  городской среды. Заключение. Изучение  взаимосвязи и установление  наиболее  важных  факторов, влияющих на процессы  нормального  течения  беременности,  родов  и состояние  новорожденного, позволяет   разрабатывать  дополнительные   критерии  для  формирования групп  повышенного  акушерского   и перинатального  риска и прогнозировать течение беременности.  Разработана математическая модель прогнозирования течения  гестационного процесса,  учитывающая выявленные дополнительные  критерии

Myofibrillogenesis regulator 1 induces hypertrophy by promoting sarcomere organization in neonatal rat cardiomyocytes

Human myofibrillogenesis regulator 1, a novel 17-kDa protein, is closely involved in cardiac hypertrophy. We studied the molecular mechanism that links MR-1 to hypertrophic response. Hypertrophic hallmarks such as cell size and [3H]-leucine incorporation were significantly increased when MR-1 was transfected into cardiomyocytes for 48 h. However, sarcomere organization was promoted when MR-1 was transfected for 8 h. The finding that cardiac hypertrophy was induced long after increase of sarcomere organization indicates that the promoted sarcomere organization may be one of the crucial factors causing hypertrophy. Furthermore, when MR-1 was transfected into cardiomyocytes, the nuclear localization of myomesin-1 was shifted to the cytoplasm. Transfection with small ubiquitin-like modifier-1 (SUMO-1) mimicked the effect of MR-1 inducing translocation of myomesin-1. However, transfection with SUMO-1 in MR-1-silenced cardiomyocytes failed to induce translocation and sarcomere organization, even though SUMO-1 expression was at the same level. Overexpression of MR-1 may induce cardiomyocyte hypertrophy via myomesin-1-mediated sarcomere organization

Different Localizations and Cellular Behaviors of Leiomodin and Tropomodulin in Mature Cardiomyocyte Sarcomeres

Lmod is a muscle-specific actin nucleator that displays structural similarity to the filament pointed-end–capping protein, Tmod. The mechanisms of localizations of Lmod and Tmod in muscle sarcomeres are strikingly different. Lmod contributes to the organization of mature myofibrils through a mechanism that requires interaction with tropomyosin

Cytoskeletal protein kinases: titin and its relations in mechanosensing

Titin, the giant elastic ruler protein of striated muscle sarcomeres, contains a catalytic kinase domain related to a family of intrasterically regulated protein kinases. The most extensively studied member of this branch of the human kinome is the Ca2+–calmodulin (CaM)-regulated myosin light-chain kinases (MLCK). However, not all kinases of the MLCK branch are functional MLCKs, and about half lack a CaM binding site in their C-terminal autoinhibitory tail (AI). A unifying feature is their association with the cytoskeleton, mostly via actin and myosin filaments. Titin kinase, similar to its invertebrate analogue twitchin kinase and likely other “MLCKs”, is not Ca2+–calmodulin-activated. Recently, local protein unfolding of the C-terminal AI has emerged as a common mechanism in the activation of CaM kinases. Single-molecule data suggested that opening of the TK active site could also be achieved by mechanical unfolding of the AI. Mechanical modulation of catalytic activity might thus allow cytoskeletal signalling proteins to act as mechanosensors, creating feedback mechanisms between cytoskeletal tension and tension generation or cellular remodelling. Similar to other MLCK-like kinases like DRAK2 and DAPK1, TK is linked to protein turnover regulation via the autophagy/lysosomal system, suggesting the MLCK-like kinases have common functions beyond contraction regulation