scholarly journals The Role of 3′ to 5′ Reverse RNA Polymerization in tRNA Fidelity and Repair

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 250 ◽  
Author(s):  
Allan W. Chen ◽  
Malithi I. Jayasinghe ◽  
Christina Z. Chung ◽  
Bhalchandra S. Rao ◽  
Rosan Kenana ◽  
...  
Keyword(s):  
Biological Functions ◽  
Protein Activity ◽  
Dna And Rna ◽  
Current State ◽  
Multiple Reactions ◽  
Rna Polymerization ◽  
Domains Of Life ◽  
The Common ◽  
Exciting Possibility

The tRNAHis guanylyltransferase (Thg1) superfamily includes enzymes that are found in all three domains of life that all share the common ability to catalyze the 3′ to 5′ synthesis of nucleic acids. This catalytic activity, which is the reverse of all other known DNA and RNA polymerases, makes this enzyme family a subject of biological and mechanistic interest. Previous biochemical, structural, and genetic investigations of multiple members of this family have revealed that Thg1 enzymes use the 3′ to 5′ chemistry for multiple reactions in biology. Here, we describe the current state of knowledge regarding the catalytic features and biological functions that have been so far associated with Thg1 and its homologs. Progress toward the exciting possibility of utilizing this unusual protein activity for applications in biotechnology is also discussed.

The Epistemic Role of Technical Functions

2020 ◽  
Author(s):  
Beth Preston
Keyword(s):  
Natural Kinds ◽  
Biological Functions ◽  
Social Functions ◽  
The Common ◽  
Technical Functions ◽  
Analysis Of Function ◽  
Epistemic Role ◽  
Special Case ◽  
The Continuum

Technical functions of artifacts are commonly distinguished from their social functions and from biological functions of organisms. Schemes for classifying functions often encounter what the author calls the continuum problem—the imperceptible merger of function kinds. This is a special case of a debate about natural kinds in philosophy of science, which has resulted in a turn to an epistemological construal of kinds, in contrast to the traditional, purely ontological construal. The author argues for an epistemic analysis of function kinds along the lines of John Dupré’s (1993) “promiscuous realism.” This provides leverage for asking new and important questions about the epistemic purposes served by our various schemes for classifying artifact functions, and about the epistemic role of technical functions in particular. The author argues that the common classification into technical, social, and biological functions has more disadvantages than it has advantages.

scholarly journals Polyamines and Their Role in Virus Infection

2017 ◽  
Vol 81 (4) ◽  
Author(s):  
Bryan C. Mounce ◽  
Michelle E. Olsen ◽  
Marco Vignuzzi ◽  
John H. Connor
Keyword(s):  
Protein Synthesis ◽  
Nucleic Acid ◽  
Mammalian Cells ◽  
Cellular Proliferation ◽  
Polyamine Synthesis ◽  
Host Interactions ◽  
Dna And Rna ◽  
Rna Polymerization ◽  
Nucleic Acid Conformation

SUMMARY Polyamines are small, abundant, aliphatic molecules present in all mammalian cells. Within the context of the cell, they play a myriad of roles, from modulating nucleic acid conformation to promoting cellular proliferation and signaling. In addition, polyamines have emerged as important molecules in virus-host interactions. Many viruses have been shown to require polyamines for one or more aspects of their replication cycle, including DNA and RNA polymerization, nucleic acid packaging, and protein synthesis. Understanding the role of polyamines has become easier with the application of small-molecule inhibitors of polyamine synthesis and the use of interferon-induced regulators of polyamines. Here we review the diverse mechanisms in which viruses require polyamines and investigate blocking polyamine synthesis as a potential broad-spectrum antiviral approach.

scholarly journals 4th International Academic Conference “Liturgical Practices and Hieratic Arts Nowadays: Prospects for the Development of Research Area” (Krasnodar, November 9–12, 2020)

2021 ◽  
pp. 141-145
Author(s):  
Svetlana Hvatova
Keyword(s):  
Human Life ◽  
Religious Practice ◽  
Research Area ◽  
Religious Practices ◽  
Current State ◽  
Academic Conference ◽  
New Information ◽  
The Common ◽  
A Current

The paper analyses the findings of the 4th International Academic Conference. The academics reported new information on the current state of religious practices of different faith communities, as well as identified the hieratic signs in the context of secular art. The reporting researchers also explored the state of the liturgical canon in a current religious practice and reviewed the sacral aspect of human life in the context of traditional religious practices. The scholars also discussed the role of hieratic art in community life, its educational and enlightening capacity, and the modern forms of representation of the sacred. For the fourth time, the common subject of the study brings together art historians, historians, culture researchers, educators, psychologists, theologians, philosophers, and a number of persons involved in spiritual enlightenment and education.

scholarly journals Controlling the delicate balance of tetrapyrrole biosynthesis

2013 ◽  
Vol 368 (1622) ◽  
pp. 20120262 ◽  
Author(s):  
Liang Yin ◽  
Carl E. Bauer
Keyword(s):  
Cellular Response ◽  
Chlorophyll Biosynthesis ◽  
Chlorophyll Synthesis ◽  
Enzymatic Reactions ◽  
Biological Processes ◽  
Protein Activity ◽  
Surrounding Environment ◽  
Cobalamin Biosynthesis ◽  
Domains Of Life ◽  
The Common

Tetrapyrroles are a family of compounds that contain four pyrrole rings. They are involved in many fundamental biological processes such as photoreception, electron transport, gas transport and also as cofactors for enzymatic reactions. As regulators of protein activity, tetrapyrroles mediate cellular response to light, oxygen and nutrient levels in the surrounding environment. Biosynthesis of haem tetrapyrroles shares, conserved pathways and enzymes among all three domains of life. This is contrasted by chlorophyll biosynthesis that is only present in eubacteria and chloroplasts, or cobalamin biosynthesis that is only present in eubacteria and archaea. This implicates haem as the most ancient, and chlorophyll as the most recent, of the common tetrapyrroles that are currently synthesized by existing organisms. Haem and chlorophyll are both toxic when synthesized in excess over apo-proteins that bind these tetrapyrroles. Accordingly, the synthesis of these tetrapyrroles has to be tightly regulated and coordinated with apo-protein production. The mechanism of regulating haem and chlorophyll synthesis has been studied intensively in Rhodobacter species and will be discussed.

scholarly journals Covalently Linking Oligomerization-Impaired GlpF Protomers Does Not Completely Re-establish Wild-Type Channel Activity

2019 ◽  
Vol 20 (4) ◽  
pp. 927 ◽  
Author(s):  
Noreen Klein ◽  
Margareta Trefz ◽  
Dirk Schneider
Keyword(s):  
Water Flux ◽  
Integral Membrane Proteins ◽  
Channel Activity ◽  
Wild Type ◽  
Protein Activity ◽  
E Coli ◽  
Domains Of Life ◽  
Linear Manner ◽  
Aquaporin Family

Integral membrane proteins of the aquaporin family facilitate rapid water flux across cellular membranes in all domains of life. Although the water-conducting pore is clearly defined in an aquaporin monomer, all aquaporins assemble into stable tetramers. In order to investigate the role of protomer–protomer interactions, we analyzed the activity of heterotetramers containing increasing fractions of mutated monomers, which have an impaired oligomerization propensity and activity. In order to enforce interaction between the protomers, we designed and analyzed a genetically fused homotetramer of GlpF, the aquaglyceroporin of the bacterium Escherichia coli (E. coli). However, increasing fractions of the oligomerization-impaired mutant GlpF E43A affected the activity of the GlpF heterotetramer in a nearly linear manner, indicating that the reduced protein activity, caused by the introduced mutations, cannot be fully compensated by simply covalently linking the monomers. Taken together, the results underline the importance of exactly positioned monomer–monomer contacts in an assembled GlpF tetramer.

scholarly journals The glycan alphabet is not universal: a hypothesis

2020 ◽  
Vol 6 (11) ◽  
Author(s):  
Jaya Srivastava ◽  
P. Sunthar ◽  
Petety V. Balaji
Keyword(s):  
Short Chain ◽  
Biosynthesis Pathway ◽  
Bacterial Genomes ◽  
Naturally Occurring ◽  
Domains Of Life ◽  
Common Group ◽  
The Common ◽  
Short Chain Dehydrogenase ◽  
Rare Group

Several monosaccharides constitute naturally occurring glycans, but it is uncertain whether they constitute a universal set like the alphabets of proteins and DNA. Based on the available experimental observations, it is hypothesized herein that the glycan alphabet is not universal. Data on the presence/absence of pathways for the biosynthesis of 55 monosaccharides in 12 939 completely sequenced archaeal and bacterial genomes are presented in support of this hypothesis. Pathways were identified by searching for homologues of biosynthesis pathway enzymes. Substantial variations were observed in the set of monosaccharides used by organisms belonging to the same phylum, genera and even species. Monosaccharides were grouped as common, less common and rare based on their prevalence in Archaea and Bacteria. It was observed that fewer enzymes are sufficient to biosynthesize monosaccharides in the common group. It appears that the common group originated before the formation of the three domains of life. In contrast, the rare group is confined to a few species in a few phyla, suggesting that these monosaccharides evolved much later. Fold conservation, as observed in aminotransferases and SDR (short-chain dehydrogenase reductase) superfamily members involved in monosaccharide biosynthesis, suggests neo- and sub-functionalization of genes led to the formation of the rare group monosaccharides. The non-universality of the glycan alphabet begets questions about the role of different monosaccharides in determining an organism’s fitness.

scholarly journals Selenium, Selenoproteins, and Female Reproduction: A Review

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3053 ◽  
Author(s):  
Izhar Qazi ◽  
Christiana Angel ◽  
Haoxuan Yang ◽  
Bo Pan ◽  
Evangelos Zoidis ◽  
...  
Keyword(s):  
Ovarian Function ◽  
Antioxidant Activities ◽  
Reproductive Function ◽  
Potential Effect ◽  
Biological Functions ◽  
Female Reproduction ◽  
Domains Of Life ◽  
Molecular And Biochemical Mechanisms ◽  
Se Status

Selenium (Se) is an essential micronutrient that has several important functions in animal and human health. The biological functions of Se are carried out by selenoproteins (encoded by twenty-five genes in human and twenty-four in mice), which are reportedly present in all three domains of life. As a component of selenoproteins, Se has structural and enzymatic functions; in the latter context it is best recognized for its catalytic and antioxidant activities. In this review, we highlight the biological functions of Se and selenoproteins followed by an elaborated review of the relationship between Se and female reproductive function. Data pertaining to Se status and female fertility and reproduction are sparse, with most such studies focusing on the role of Se in pregnancy. Only recently has some light been shed on its potential role in ovarian physiology. The exact underlying molecular and biochemical mechanisms through which Se or selenoproteins modulate female reproduction are largely unknown; their role in human pregnancy and related complications is not yet sufficiently understood. Properly powered, randomized, controlled trials (intervention vs. control) in populations of relatively low Se status will be essential to clarify their role. In the meantime, studies elucidating the potential effect of Se supplementation and selenoproteins (i.e., GPX1, SELENOP, and SELENOS) in ovarian function and overall female reproductive efficiency would be of great value.

On everyday academic research

2017 ◽  
pp. 98-134 ◽  
Author(s):  
J. Tirole
Keyword(s):  
Common Good ◽  
Academic Research ◽  
Research Quality ◽  
Economic Research ◽  
Relevant Research ◽  
The Common ◽  
Verification Of Models ◽  
Science And Research

In the fourth chapter of the book “The economy of the common good”, the nature of economics as a science and research practices in their theoretical and empirical aspects are discussed. The author considers the processes of modeling, empirical verification of models and evaluation of research quality. In addition, the features of economic cognition and the role of mathematics in economic research are analyzed, including the example of relevant research in game theory and information theory.

Contemplative Principles of a Non-dual Praxis: the Unmediated Practices of the Tibetan ‘Heart Essence’ (sNying thig) Tradition

2015 ◽  
Vol 31 (2) ◽  
pp. 215-240
Author(s):  
Eran Laish
Keyword(s):  
Contemplative Practice ◽  
Tibetan Buddhist ◽  
Buddhist Tradition ◽  
The Common

This article focuses on the main contemplative principles of the ‘Heart Essence’ (sNying thig), a Tibetan Buddhist tradition that is characterized by a vision of non-duality and primordial wholeness. Due to this vision, which asserts an original reality that is not divided into perceiving subject and perceived object, the ‘Heart Essence’ advocates a contemplative practice that undermines the usual intuitions of temporality and enclosed selfhood. Hence, unlike the common principles of intentional praxis, such as deliberate concentration and gradual purification, the ‘Heart Essence’ affirms four contemplative principles of non-objectiveness, openness, spontaneity and singleness. As these principles transcend intentionality, temporality, and multiplicity, they are seen to directly disclose the nature of primordial awareness, in which the meanings of knowing and being are radically transformed. Therefore, the article will also consider the role of these non-dual contemplative principles in deeply changing our understanding of being and knowing alike.

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