scholarly journals Mammalian cells contain a second nucleocytoplasmic hexosaminidase

2009 ◽  
Vol 419 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Martin Gutternigg ◽  
Dubravko Rendić ◽  
Regina Voglauer ◽  
Thomas Iskratsch ◽  
Iain B. H. Wilson

Some thirty years ago, work on mammalian tissues suggested the presence of two cytosolic hexosaminidases in mammalian cells; one of these has been more recently characterized in a recombinant form and has an important role in cellular function due to its ability to cleave β-N-acetylglucosamine residues from a variety of nuclear and cytoplasmic proteins. However, the molecular nature of the second cytosolic hexosaminidase, named hexosaminidase D, has remained obscure. In the present study, we molecularly characterize for the first time the human and murine recombinant forms of enzymes, encoded by HEXDC genes, which appear to correspond to hexosaminidase D in terms of substrate specificity, pH dependency and temperature stability. Furthermore, a Myc-tagged form of this novel hexosaminidase displays a nucleocytoplasmic localization. Transcripts of the corresponding gene are expressed in a number of murine tissues. On the basis of its sequence, this enzyme represents, along with the lysosomal hexosaminidase subunits encoded by the HEXA and HEXB genes, the third class 20 glycosidase to be identified from mammalian sources.

2011 ◽  
Vol 77 (7) ◽  
pp. 2471-2478 ◽  
Author(s):  
Guiomar Sánchez-Carrón ◽  
María Inmaculada García-García ◽  
Ana Belén López-Rodríguez ◽  
Sofía Jiménez-García ◽  
Agustín Sola-Carvajal ◽  
...  

ABSTRACTN-Acetylneuraminate lyases (NALs) or sialic acid aldolases catalyze the reversible aldol cleavage ofN-acetylneuraminic acid (Neu5Ac) to form pyruvate andN-acetyl-d-mannosamine (ManNAc). In nature,N-acetylneuraminate lyase occurs mainly in pathogens. However, this paper describes how anN-acetylneuraminate lyase was cloned from the human gut commensalLactobacillus plantarumWCFS1 (LpNAL), overexpressed, purified, and characterized for the first time. This novel enzyme, which reaches a high expression level (215 mg liter−1culture), shows similar catalytic efficiency to the best NALs previously described. This homotetrameric enzyme (132 kDa) also shows high stability and activity at alkaline pH (pH > 9) and good temperature stability (60 to 70°C), this last feature being further improved by the presence of stabilizing additives. These characteristics make LpNAL a promising biocatalyst. When its sequence was compared with that of other, related (real and putative) NALs described in the databases, it was seen that NAL enzymes could be divided into four structural groups and three subgroups. The relation of these subgroups with human and other mammalian NALs is also discussed.


Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 481
Author(s):  
Gemma G. Martínez-García ◽  
Raúl F. Pérez ◽  
Álvaro F. Fernández ◽  
Sylvere Durand ◽  
Guido Kroemer ◽  
...  

Autophagy is an essential protective mechanism that allows mammalian cells to cope with a variety of stressors and contributes to maintaining cellular and tissue homeostasis. Due to these crucial roles and also to the fact that autophagy malfunction has been described in a wide range of pathologies, an increasing number of in vivo studies involving animal models targeting autophagy genes have been developed. In mammals, total autophagy inactivation is lethal, and constitutive knockout models lacking effectors of this route are not viable, which has hindered so far the analysis of the consequences of a systemic autophagy decline. Here, we take advantage of atg4b−/− mice, an autophagy-deficient model with only partial disruption of the process, to assess the effects of systemic reduction of autophagy on the metabolome. We describe for the first time the metabolic footprint of systemic autophagy decline, showing that impaired autophagy results in highly tissue-dependent alterations that are more accentuated in the skeletal muscle and plasma. These changes, which include changes in the levels of amino-acids, lipids, or nucleosides, sometimes resemble those that are frequently described in conditions like aging, obesity, or cardiac damage. We also discuss different hypotheses on how impaired autophagy may affect the metabolism of several tissues in mammals.


1989 ◽  
Vol 26 (3) ◽  
pp. 591-605 ◽  
Author(s):  
David J. Mossman ◽  
Craig H. Place

Vertebrate trace fossils are reported for the first time from red beds near the top of megacyclic sequence II at Prim Point in southwestern Prince Edward Island. They occur as casts of tetrapod trackways. The ichnocoenose also includes a rich invertebrate ichnofauna. The trackmakers thrived in an area of sparse vegetation and occupied out-of-channel river sediments, most likely crevasse-splay deposits.Amphisauropus latus, represented by three trackways, has been previously reported from Germany, Poland, and Czechoslovakia. It is here interpreted as the track of a cotylosaur. It occurs together with the track of Gilmoreichnus kablikae, which is either a captorhinomorph or possibly a juvenile pelycosaur. These facilitate the assignment of a late Early Permian (late Autunian) age to the strata. The third set of footprints, those of a small herbivorous pelycosaur, compare most closely with Ichniotherium willsi, known hitherto from the Keele beds (latest Stephanian) of the English Midlands.This ichnocoenose occurs in a plate-tectonically rafted segment of crust stratigraphically equivalent to the same association of ichnofauna in the English Midlands and central Europe. The community occupied piedmont-valley-flat red beds within the molasse facies of Variscan uplands.


2000 ◽  
Vol 655 ◽  
Author(s):  
Jung-Hyuk Koh ◽  
S.I. Khartsev ◽  
Alex Grishin ◽  
Vladimir Petrovsky

AbstractFor the first time AgTa0.38Nb0.62O3 (ATN) films have been grown on the La0.7Sr0.3CoO3 (LSCO)/LaAlO3 single crystal as well as onto Pt80Ir20 (PtIr) polycrystalline substrate. Comprehensive X-ray diffraction analyses reveal epitaxial quality of ATN and LSCO films on the LaAlO3(001) substrate, while ATN/PtIr films have been found to be (001) preferentially oriented. Dielectric spectroscopy performed for ATN films and bulk ceramics in a wide temperature range 77 to 420 K shows the structural monoclinic M1-to-monoclinic M2 phase transition occurs in films at the temperature 60 °C lower than in ceramics. The tracing of the ferroelectric hysteresis P-E loops indicates the ferroelectric state in ATN films at temperatures below 125 K and yields remnant polarization of 0.4 μC/cm2 @ 77 K. Weak frequency dispersion, high temperature stability of dielectric properties as well as low processing temperature of 550 °C make ATN films to be attractive for various applications.


1995 ◽  
Vol 400 ◽  
Author(s):  
R.T. Malkhassian

AbstractA new technology for obtainment of amorphous single-component metals is presented.For the first time the reduction of molybdenum oxide with formation of its amorphous phase is realized in conditions of a given quantum-chemical technology by means of vibrationally excited to the third quantum level hydrogen molecules with 1.5 ± 0.2 eV energy. The evidences of formation of this nonequilibrium amorphous phase are presented along with certain physicochemical properties of the obtained amorphous molybdenum.A model is proposed for the origin of amorphous phase under the influence of nonequilibrium quantum-chemical technology.


2021 ◽  
Vol 66 (1) ◽  
pp. 329-343
Author(s):  
Liudmyla Shapovalova ◽  
Іryna Romaniuk ◽  
Marianna Chernyavska ◽  
Svitlana Shchelkanova

"In the article under consideration are the ways of symphony genre transformation in the early works of Valentin Silvestrov (Ukraine). For the first time, the First, Second, Third, and Fourth symphonies by the genius composers of the 20th century are analyzed as a certain stylistic system. These compositions are endowed with the features of avant-garde poetics, and as a subject of musicological reflection, they are associated with a rethinking of the semantic paradigm of the genre. V. Silvestrov's early symphonies stand out from the classical practice of European symphonies. Scientific awareness of their phenomenal nature necessitated a methodological choice aimed at the most accurate identification of the philosophical concept of the new sound universum of V. Silvestrov's music. Deep correlation of the image of a human being as a factor of the symphony poetics (the influence of philosophical concepts of human ontology in the 20th century with the transformation of the genre canon) is considered. This refers to the nonmusical dimension of the genre semantics. The study of V. Silvestrov's early symphonies reveal a new philosophy of music through gradual movement – modulation: from the neo-baroque First Symphony and ""cosmic pastorals"" Musica Mundana of the Second Symphony through the history anthropologisation in the Third Symphony ""Eschatology"" to the monodrama Musica Humana in the Fourth Symphony. The dichotomy of Musica Mundana – Musica Humana is not accidental: in V. Silvestrov's creative method, remains relevant, which is confirmed by the dramaturgy of his latest work – the Ninth symphony (2019). Keywords: V. Silvestrov's early symphonies, evolution of style, worldview, Musica Mundana, monodrama. "


2021 ◽  
pp. 1-22
Author(s):  
Tofigh Maboudi ◽  
Ghazal P. Nadi ◽  
Todd A. Eisenstadt

Abstract Since the third wave of democracy, term limits have become a popular fixture of most constitutions intended to constrain the executive. Yet, recent constitutional reforms around the world show that presidents seeking re-election sometimes overturn the entire constitutional order to extend their power. What is the impact of these constitutional manipulations on the longevity of the executive in office? Using survival analysis of all political leaders and national constitutions from 1875 to 2015, this article demonstrates, for the first time, that when ‘authoritarian-aspiring’ presidents remove constitutional term limits, they increase their stay in office by more than 40%. Our findings contrast with a widely held position in the comparative authoritarian literature suggesting that dictators survive longer under institutional constraints. On the contrary, we argue that by removing constitutional barriers, rulers consolidate more power at the expense of their most ambitious allies and can stay in power longer.


Author(s):  
Т.А. Богумил

В статье предлагается концепция жизни и творческого роста В.М. Шукшина сквозь призму тезаурусного и кластерного подходов. Объяснительными «персональными моделями» для интерпретации биографического текста писателя являются кластеры Мартина Идена, Гамлета и Степана Разина. Ранее биографы и литературоведы указывали на важность этих персон для Шукшина, но разрозненно. Впервые предпринята попытка свести указанные персональные модели воедино, в целостный сюжет становления писателя в пространстве культуры. На разных этапах эволюции автора доминирует одна из указанных моделей, последовательно сменяя друг друга, но не вытесняя, а «внахлест». Ранний этап творчества, ориентированный на стратегию Мартина Идена, является попыткой «вписаться» в наличный культурный мейнстрим. Выражено это в следовании поэтике соцреализма. Второй этап подспудно начинается с реабилитации отца Шукшина в 1956 года, когда актуализируется «гамлетовский комплекс», проявляющийся в чувстве вины перед отцом, через стратегию утаивания подлинного «я», мотивы чудаковатости. Третий этап связан с личностью реального исторического лица, Степана Разина, и выражается в открытом протесте против власти. Все важные для В.М. Шукшина поведенческие модели объединены мотивом одинокого противостояния враждебному социуму и имеют трагический финал, что обусловило ранний уход писателя и порождение мифов о насильственном характере его смерти. В.М. Шукшин одновременно был фигурой неординарной и типичной, что позволило его биографии стать «персональной моделью» для последующих авторов, выходцев из сельской глубинки. The article proposes the concept of life and creative growth of V.M. Shukshin through the prism of the thesaurus and cluster approach. The explanatory "personal models" for interpreting the biographical text of the writer are clusters of Martin Eden, Hamlet and Stepan Razin. Earlier, biographers and literary critics pointed out the importance of these people for Shukshin, but it was scattered. For the first time, an attempt was made to bring these personal models together into an integral plot of the formation of the writer in the space of culture. At different stages of the writer’s evolution, one of these models dominates, successively replacing each other, but not crowding out, but “overlapping”. The early stage of creativity, focused on Martin Eden’s strategy, is an attempt to “fit in” the current cultural mainstream. This is expressed in following the poetics of socialist realism. The second stage implicitly begins with the rehabilitation of Shukshin’s father in 1956, when the “Hamletian complex” is actualized. It is manifested in a sense of guilt towards his father, the strategy of concealing the true “I”, eccentricities. The third stage is connected with the personality of a real historical person, Stepan Razin, and is expressed in an open protest against the authorities. All important for V.M. Shukshin's behavioral models are united by the motive of a lonely confrontation with a hostile society and have a tragic ending, which led to the early departure of the writer and the generation of myths about the violent nature of his death. V.M. Shukshin was an extraordinary and typical figure at the same time. That allowed his biography to become a “personal model” for subsequent authors who came from the rural outback.


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