scholarly journals Phylogenetic evidence for homologous recombination within the family Birnaviridae

2008 ◽  
Vol 89 (12) ◽  
pp. 3156-3164 ◽  
Author(s):  
Chung-Chau Hon ◽  
Tommy Tsan-Yuk Lam ◽  
Chi-Wai Yip ◽  
Raymond Tsz-Yeung Wong ◽  
Mang Shi ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Live Attenuated Vaccine ◽  
Double Stranded Rna ◽  
Live Vaccines ◽  
Naturally Occurring ◽  
Wide Range ◽  
The Family ◽  
Bursal Disease ◽  
Comprehensive Survey ◽  
Dsrna Viruses

Birnaviruses are bi-segmented double-stranded RNA (dsRNA) viruses infecting insects, avian species and a wide range of aquatic species. Although homologous recombination is a common phenomenon in positive-sense RNA viruses, recombination in dsRNA viruses is rarely reported. Here we performed a comprehensive survey on homologous recombination in all available sequences (>1800) of the family Birnaviridae based on phylogenetic incongruence. Although inter-species recombination was not evident, potential intra-species recombination events were detected in aquabirnaviruses and infectious bursal disease virus (IBDV). Eight potential recombination events were identified and the possibility that these events were non-naturally occurring was assessed case by case. Five of the eight events were identified in IBDVs and all of these five events involved live attenuated vaccine strains. This finding suggests that homologous recombination between vaccine and wild-type IBDV strains may have occurred; the potential risk of mass vaccination using live vaccines is discussed. This is the first report of evidence for homologous recombination within the family Birnaviridae.

scholarly journals Heterodimers as the Structural Unit of the T=1 Capsid of the Fungal Double-Stranded RNA Rosellinia necatrix Quadrivirus 1

2016 ◽  
Vol 90 (24) ◽  
pp. 11220-11230 ◽  
Author(s):  
Daniel Luque ◽  
Carlos P. Mata ◽  
Fernando González-Camacho ◽  
José M. González ◽  
Josué Gómez-Blanco ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Molecular Sieves ◽  
Three Dimensional ◽  
Rosellinia Necatrix ◽  
Double Stranded Rna ◽  
Content Type ◽  
Cryo Electron Microscopy ◽  
Wide Range ◽  
The Family ◽  
Dsrna Viruses

ABSTRACTMost double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts. Rosellinia necatrix quadrivirus 1 (RnQV1), the type species of the familyQuadriviridae, is a dsRNA fungal virus with a multipartite genome consisting of four monocistronic segments (segments 1 to 4). dsRNA-2 and dsRNA-4 encode two CPs (P2 and P4, respectively), which coassemble into ∼450-Å-diameter capsids. We used three-dimensional cryo-electron microscopy combined with complementary biophysical techniques to determine the structures of RnQV1 virion strains W1075 and W1118. RnQV1 has a quadripartite genome, and the capsid is based on a single-shelled T=1 lattice built of P2-P4 dimers. Whereas the RnQV1-W1118 capsid is built of full-length CP, P2 and P4 of RnQV1-W1075 are cleaved into several polypeptides, maintaining the capsid structural organization. RnQV1 heterodimers have a quaternary organization similar to that of homodimers of reoviruses and other dsRNA mycoviruses. The RnQV1 capsid is the first T=1 capsid with a heterodimer as an asymmetric unit reported to date and follows the architectural principle for dsRNA viruses that a 120-subunit capsid is a conserved assembly that supports dsRNA replication and organization.IMPORTANCEGiven their importance to health, members of the familyReoviridaeare the basis of most structural and functional studies and provide much of our knowledge of dsRNA viruses. Analysis of bacterial, protozoal, and fungal dsRNA viruses has improved our understanding of their structure, function, and evolution, as well. Here, we studied a dsRNA virus that infects the fungusRosellinia necatrix, an ascomycete that is pathogenic to a wide range of plants. Using three-dimensional cryo-electron microscopy and analytical ultracentrifugation analysis, we determined the structure and stoichiometry of Rosellinia necatrix quadrivirus 1 (RnQV1). The RnQV1 capsid is a T=1 capsid with 60 heterodimers as the asymmetric units. The large amount of genetic information used by RnQV1 to construct a simple T=1 capsid is probably related to the numerous virus-host and virus-virus interactions that it must face in its life cycle, which lacks an extracellular phase.

scholarly journals A cypovirus VP5 displays the RNA chaperone-like activity that destabilizes RNA helices and accelerates strand annealing

2013 ◽  
Vol 42 (4) ◽  
pp. 2538-2554 ◽  
Author(s):  
Jie Yang ◽  
Zhenyun Cheng ◽  
Songliu Zhang ◽  
Wei Xiong ◽  
Hongjie Xia ◽  
...  
Keyword(s):  
Replication Initiation ◽  
Simplified Model ◽  
Divalent Ions ◽  
Direct Role ◽  
Rna Chaperone ◽  
Double Stranded Rna ◽  
The Family ◽  
Dsrna Viruses ◽  
Strand Annealing

Abstract For double-stranded RNA (dsRNA) viruses in the family Reoviridae, their inner capsids function as the machinery for viral RNA (vRNA) replication. Unlike other multishelled reoviruses, cypovirus has a single-layered capsid, thereby representing a simplified model for studying vRNA replication of reoviruses. VP5 is one of the three major cypovirus capsid proteins and functions as a clamp protein to stabilize cypovirus capsid. Here, we expressed VP5 from type 5 Helicoverpa armigera cypovirus (HaCPV-5) in a eukaryotic system and determined that this VP5 possesses RNA chaperone-like activity, which destabilizes RNA helices and accelerates strand annealing independent of ATP. Our further characterization of VP5 revealed that its helix-destabilizing activity is RNA specific, lacks directionality and could be inhibited by divalent ions, such as Mg2+, Mn2+, Ca2+ or Zn2+, to varying degrees. Furthermore, we found that HaCPV-5 VP5 facilitates the replication initiation of an alternative polymerase (i.e. reverse transcriptase) through a panhandle-structured RNA template, which mimics the 5′-3′ cyclization of cypoviral positive-stranded RNA. Given that the replication of negative-stranded vRNA on the positive-stranded vRNA template necessitates the dissociation of the 5′-3′ panhandle, the RNA chaperone activity of VP5 may play a direct role in the initiation of reoviral dsRNA synthesis.

Turmeric

2020 ◽  
pp. 163-172
Author(s):  
Mazia Ahmed ◽  
Urvashi Srivastava ◽  
Chitra Gupta
Keyword(s):  
Biological Activities ◽  
Curcuma Longa ◽  
Healthy Food ◽  
Natural Food ◽  
Food Ingredient ◽  
Tropical Regions ◽  
Naturally Occurring ◽  
Diverse Field ◽  
Wide Range ◽  
The Family

Turmeric (Curcuma longa) is a rhizomatous crop found in tropical regions and belongs to the family Zingiberaceae. It was used in the form of a spice, flavoring substance, coloring agent, and as a therapeutic agent for the treatment of several human ailments for centuries. Turmeric, along with its extracts, has a very broad and diverse field of application. It is an exclusive and versatile naturally occurring plant product having properties of not only a spice but also food colorant, medicine or drug, and cosmetics. In ethnic delicacies, turmeric is a commonly used flavoring ingredient. It is also a popularly used natural food color. It exhibits several biological activities such as having antioxidant, anti-inflammatory, anticarcinogenic, antimutagenic, antimicrobial, antiviral, and antiparasitic properties. It is well known as a skincare product and a healthy food ingredient. It is found to have the capability to prevent or retard a wide range of ailments.

scholarly journals Purified Recombinant Bluetongue Virus VP1 Exhibits RNA Replicase Activity

2004 ◽  
Vol 78 (8) ◽  
pp. 3994-4002 ◽  
Author(s):  
Mark Boyce ◽  
Josa Wehrfritz ◽  
Rob Noad ◽  
Polly Roy
Keyword(s):  
Viral Genome ◽  
Bluetongue Virus ◽  
De Novo ◽  
Surveillance Systems ◽  
Sequence Specificity ◽  
Core Particle ◽  
Double Stranded Rna ◽  
The Family ◽  
Capping Enzyme ◽  
Dsrna Viruses

ABSTRACT The polymerase protein of all known double-stranded RNA (dsRNA) viruses is located within a complex subviral core particle that is responsible for transcription of the viral genome. For members of the family Reoviridae, this particle allows messenger sense RNA synthesis while sequestering the viral genome away from cellular dsRNA surveillance systems during infection of eukaryotic cells. The core particle of bluetongue virus (BTV) consists of the major structural proteins VP3 and VP7 and the minor enzymatic proteins VP1 (polymerase), VP4 (capping enzyme), and VP6 (helicase). In this report we have characterized fully processive dsRNA synthesis by VP1 from a viral plus-strand RNA template in the absence of the other proteins of the BTV core. This replicase activity consists of de novo initiation of synthesis, followed by elongation of the minus strand. Purified VP1 exhibits little sequence specificity for BTV plus-strand template, suggesting that the choice of viral over nonviral RNA template comes from its association with other proteins within the viral core.

scholarly journals Naturally occurring van der Waals materials

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Riccardo Frisenda ◽  
Yue Niu ◽  
Patricia Gant ◽  
Manuel Muñoz ◽  
Andres Castellanos-Gomez
Keyword(s):  
Crystal Structures ◽  
Scientific Community ◽  
2D Materials ◽  
Van Der Waals ◽  
Chemical Compositions ◽  
Naturally Occurring ◽  
Wide Range ◽  
The Family ◽  
Materials Research ◽  
Van Der Waals Materials

Abstract The exfoliation of two naturally occurring van der Waals minerals, graphite and molybdenite, arouse an unprecedented level of interest by the scientific community and shaped a whole new field of research: 2D materials research. Several years later, the family of van der Waals materials that can be exfoliated to isolate 2D materials keeps growing, but most of them are synthetic. Interestingly, in nature, plenty of naturally occurring van der Waals minerals can be found with a wide range of chemical compositions and crystal structures whose properties are mostly unexplored so far. This Perspective aims to provide an overview of different families of van der Waals minerals to stimulate their exploration in the 2D limit.

scholarly journals Comparison of Polymerase Subunits from Double-Stranded RNA Bacteriophages

2001 ◽  
Vol 75 (22) ◽  
pp. 11088-11095 ◽  
Author(s):  
Hongyan Yang ◽  
Eugene V. Makeyev ◽  
Dennis H. Bamford
Keyword(s):  
Molecular Basis ◽  
Rna Synthesis ◽  
Regulatory Mechanism ◽  
Biochemical Properties ◽  
Double Stranded Rna ◽  
The Family ◽  
Dsrna Viruses ◽  
Template Specificity

ABSTRACT The family Cystoviridae comprises several bacteriophages with double-stranded RNA (dsRNA) genomes. We have previously purified the catalytic polymerase subunit (Pol) of one of the Cystoviridae members, bacteriophage φ6, and shown that the protein can catalyze RNA synthesis in vitro. In this reaction, both bacteriophage-specific and heterologous RNAs can serve as templates, but those containing 3′ termini from the φ6 minus strands are favored. This provides a molecular basis for the observation that only plus strands, not minus strands, are transcribed from φ6 dsRNA segments in vivo. To test whether such a regulatory mechanism is also found in other dsRNA viruses, we purified recombinant Pol subunits from the φ6-related bacteriophages φ8 and φ13 and assayed their polymerase activities in vitro. The enzymes catalyze template-dependent RNA synthesis using both single-stranded-RNA (ssRNA) and dsRNA templates. However, they differ from each other as well as from φ6 Pol in certain biochemical properties. Notably, each polymerase demonstrates a distinct preference for ssRNAs bearing short 3′-terminal sequences from the virus-specific minus strands. This suggests that, in addition to other factors, RNA transcription inCystoviridae is controlled by the template specificity of the polymerase subunit.

Towards Understanding the Structural Requirements for Endogenous Transcription in Rotavirus

1998 ◽  
Vol 4 (S2) ◽  
pp. 1050-1051
Author(s):  
J. A. Lawton ◽  
M. K. Estes ◽  
B. V. Venkataram Prasad
Keyword(s):  
Structural Integrity ◽  
Structural Complexity ◽  
Cell Entry ◽  
Structural Studies ◽  
Double Stranded Rna ◽  
Severe Diarrhea ◽  
The Family ◽  
Causative Agents ◽  
Icosahedral Viruses ◽  
Dsrna Viruses

Rotaviruses are complex, relatively large (1000 Å) nonenveloped icosahedral viruses. They are the major causative agents of severe diarrhea in children and animals. Annually an estimated 1 million children die from rotavirus-induced gastroenteritis worldwide. Medical relevance, intriguing structural complexity, and several unique strategies in the morphogenesis and replication have provoked extensive molecular biological and structural studies on rotaviruses in recent years.Rotaviruses are double-stranded RNA (dsRNA) viruses belonging to the family Reoviridae. Each of the 11 segments codes for one protein. Of the eleven proteins encoded by the genomic RNA, six are structural and five are non-structural. Structural studies have shown that mature rotaviruses are triple-layered particles (TLPs). During the process of cell entry the outer-most layer consisting of VP7 and the spike protein VP4 is lost and the resulting double layered particles (DLPs) become transcriptionally active (Fig. 1 A). During the process of transcription, the DLPs maintain their structural Integrity.

scholarly journals Two Distinct Mechanisms Ensure Transcriptional Polarity in Double-Stranded RNA Bacteriophages

2003 ◽  
Vol 77 (2) ◽  
pp. 1195-1203 ◽  
Author(s):  
Hongyan Yang ◽  
Eugene V. Makeyev ◽  
Sarah J. Butcher ◽  
Aušra Gaidelytė ◽  
Dennis H. Bamford
Keyword(s):  
Minor Component ◽  
Rna Transcription ◽  
Double Stranded Rna ◽  
Complex Particle ◽  
Wide Range ◽  
Dsrna Viruses ◽  
Strand Initiation ◽  
A Minor

ABSTRACT In most double-stranded RNA (dsRNA) viruses, RNA transcription occurs inside a polymerase (Pol) complex particle, which contains an RNA-dependent RNA Pol subunit as a minor component. Only plus- but not minus-sense copies of genomic segments are produced during this reaction. In the case of φ6, a dsRNA bacteriophage from the Cystoviridae family, isolated Pol synthesizes predominantly plus strands using virus-specific dsRNAs in vitro, thus suggesting that Pol template preferences determine the transcriptional polarity. Here, we dissect transcription reactions catalyzed by Pol complexes and Pol subunits of two other cystoviruses, φ8 and φ13. While both Pol complexes synthesize exclusively plus strands over a wide range of conditions, isolated Pol subunits can be stimulated by Mn2+ to produce minus-sense copies on φ13 dsRNA templates. Importantly, all three Pol subunits become more prone to the native-like plus-strand synthesis when the dsRNA templates (including φ13 dsRNA) are activated by denaturation before the reaction. Based on these and earlier observations, we propose a model of transcriptional polarity in Cystoviridae controlled on two independent levels: Pol affinity to plus-strand initiation sites and accessibility of these sites to the Pol in a single-stranded form.

Quantitative and Qualitative Methods of Studying the Processes of Socialization of a Modern Teenager

2020 ◽  
pp. 102-109
Author(s):  
Svetlana Alekseevna Raschetina ◽  
Keyword(s):  
Research Methods ◽  
Interpersonal Relations ◽  
Internet Communication ◽  
Socialization Process ◽  
Wide Range ◽  
The Family ◽  
Modern Family ◽  
Making Friends ◽  
Main Support

Relevance and problem statement. Modern unstable society is characterized by narrowing the boundaries of controlled socialization and expanding the boundaries of spontaneous socialization of a teenager based on his immersion in the question arises about the importance of the family in the process of socialization of a teenager in the conditions of expanding the space of socialization. There is a need to study the role of the family in this process, to search, develop and test research methods that allow us to reveal the phenomenon of socialization from the side of its value characteristics. The purpose and methodology of the study: to identify the possibilities of a systematic and anthropological methodology for studying the role of the family in the process of socialization of adolescents in modern conditions, testing research methods: photo research on the topic “Ego – I” (author of the German sociologist H. Abels), profile update reflexive processes (by S. A. Raschetina). Materials and results of the study. The study showed that for all the problems that exist in the family of the perestroika era and in the modern family, it acts for a teenager as a value and the first (main) support in the processes of socialization. The positions well known in psychology about the importance of interpersonal relations in adolescence for the formation of attitudes towards oneself as the basis of socialization are confirmed. Today, the frontiers of making friends have expanded enormously on the basis of Internet communication. The types of activities of interest to a teenager (traditional and new ones related to digitalization) are the third pillar of socialization. Conclusion. The “Ego – I” method of photo research has a wide range of possibilities for quantitative and qualitative analysis of the socialization process to identify the value Pillars of this process.

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