scholarly journals Evolution of Persistent Viruses in Plants

2016 ◽  
pp. 263-272 ◽  
Author(s):  
Marilyn J. Roossinck
Keyword(s):  
Persistent Viruses

scholarly journals Genetic diversity and evolution of hepatitis C virus – 15 years on

2004 ◽  
Vol 85 (11) ◽  
pp. 3173-3188 ◽  
Author(s):  
Peter Simmonds
Keyword(s):  
Genetic Diversity ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Human Liver ◽  
Large Population ◽  
Sequence Divergence ◽  
Selection Pressures ◽  
Host Interactions ◽  
Persistent Viruses ◽  
The Face

In the 15 years since the discovery of hepatitis C virus (HCV), much has been learned about its role as a major causative agent of human liver disease and its ability to persist in the face of host-cell defences and the immune system. This review describes what is known about the diversity of HCV, the current classification of HCV genotypes within the family Flaviviridae and how this genetic diversity contributes to its pathogenesis. On one hand, diversification of HCV has been constrained by its intimate adaptation to its host. Despite the >30 % nucleotide sequence divergence between genotypes, HCV variants nevertheless remain remarkably similar in their transmission dynamics, persistence and disease development. Nowhere is this more evident than in the evolutionary conservation of numerous evasion methods to counteract the cell's innate antiviral defence pathways; this series of highly complex virus–host interactions may represent key components in establishing its ‘ecological niche’ in the human liver. On the other hand, the mutability and large population size of HCV enables it to respond very rapidly to new selection pressures, manifested by immune-driven changes in T- and B-cell epitopes that are encountered on transmission between individuals with different antigen-recognition repertoires. If human immunodeficiency virus type 1 is a precedent, future therapies that target virus protease or polymerase enzymes may also select very rapidly for antiviral-resistant mutants. These contrasting aspects of conservatism and adaptability provide a fascinating paradigm in which to explore the complex selection pressures that underlie the evolution of HCV and other persistent viruses.

scholarly journals Factors Determining Transmission of Persistent Viruses by Bemisia tabaci and Emergence of New Virus–Vector Relationships

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1808
Author(s):  
Saptarshi Ghosh ◽  
Murad Ghanim
Keyword(s):  
Bemisia Tabaci ◽  
Plant Viruses ◽  
Tomato Yellow Leaf ◽  
Tissue Tropism ◽  
Insect Vectors ◽  
Virus Species ◽  
Yellow Leaf ◽  
Virus Diseases ◽  
Persistent Viruses ◽  
Leaf Curl Virus

Many plant viruses depend on insect vectors for their transmission and dissemination. The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important virus vectors, transmitting more than four hundred virus species, the majority belonging to begomoviruses (Geminiviridae), with their ssDNA genomes. Begomoviruses are transmitted by B. tabaci in a persistent, circulative manner, during which the virus breaches barriers in the digestive, hemolymph, and salivary systems, and interacts with insect proteins along the transmission pathway. These interactions and the tissue tropism in the vector body determine the efficiency and specificity of the transmission. This review describes the mechanisms involved in circulative begomovirus transmission by B. tabaci, focusing on the most studied virus in this regard, namely the tomato yellow leaf curl virus (TYLCV) and its closely related isolates. Additionally, the review aims at drawing attention to the recent knowhow of unorthodox virus—B. tabaci interactions. The recent knowledge of whitefly-mediated transmission of two recombinant poleroviruses (Luteoviridae), a virus group with an ssRNA genome and known to be strictly transmitted with aphids, is discussed with its broader context in the emergence of new whitefly-driven virus diseases.

scholarly journals Molecular basis of disregulation of programmed lymphocytes’ death in chronic viral infection

2006 ◽  
Vol 5 (2) ◽  
pp. 23-34
Author(s):  
V. V. Novitsky ◽  
N. V. Ryazantseva ◽  
O. B. Zhoukova
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Viral Infection ◽  
Immune Cells ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Recent Literature ◽  
Chronic Viral Infection ◽  
Persistent Viruses

The review analyses information from recent literature and results of the authors’ own investigations concerning imbalance of programmed cell death in forming chronic viral infection. Molecular mechanisms of apoptosis modulation of immune cells by persistent viruses are discussed in the article.

scholarly journals Genomics Insights: The DNA Habitat and its RNA Inhabitants: At the Dawn of RNA Sociology

2013 ◽  
Vol 6 ◽  
pp. GEI.S11490 ◽  
Author(s):  
Luis P. Villarreal ◽  
Guenther Witzany
Keyword(s):  
Genetic Code ◽  
Evolutionary Novelty ◽  
Agent Based ◽  
Cellular Processes ◽  
Genetic Codes ◽  
Physical Chemical ◽  
Persistent Viruses ◽  
Virus Research ◽  
Biological Concepts ◽  
Regulatory Rnas

Most molecular biological concepts derive from physical chemical assumptions about the genetic code that are basically more than 40 years old. Additionally, systems biology, another quantitative approach, investigates the sum of interrelations to obtain a more holistic picture of nucleotide sequence order. Recent empirical data on genetic code compositions and rearrangements by mobile genetic elements and noncoding RNAs, together with results of virus research and their role in evolution, does not really fit into these concepts and compel a reexamination. In this review, we try to find an alternate hypothesis. It seems plausible now that if we look at the abundance of regulatory RNAs and persistent viruses in host genomes, we will find more and more evidence that the key players that edit the genetic codes of host genomes are consortia of RNA agents and viruses that drive evolutionary novelty and regulation of cellular processes in all steps of development. This agent-based approach may lead to a qualitative RNA sociology that investigates and identifies relevant behavioral motifs of cooperative RNA consortia. In addition to molecular biological perspectives, this may lead to a better understanding of genetic code evolution and dynamics.

scholarly journals Human memory T cells with a naive phenotype accumulate with aging and respond to persistent viruses

2016 ◽  
Vol 17 (8) ◽  
pp. 966-975 ◽  
Author(s):  
Vesna Pulko ◽  
John S Davies ◽  
Carmine Martinez ◽  
Marion C Lanteri ◽  
Michael P Busch ◽  
...  
Keyword(s):  
T Cells ◽  
Memory T Cells ◽  
Human Memory ◽  
Persistent Viruses

scholarly journals Studies on the transmission of sugar-beet yellows virus by the aphis, Myzus persicae (Sulz.)

1940 ◽  
Vol 128 (853) ◽  
pp. 535-552 ◽  
Keyword(s):  
Sugar Beet ◽  
Myzus Persicae ◽  
Plant Viruses ◽  
Insect Vectors ◽  
Source Of Infection ◽  
Persistent Viruses ◽  
Beet Yellows Virus ◽  
The Relationship

Previous studies on the relationship between plant viruses and their insect vectors have been carried out which viruses which are easily mechanically transmissible and whose vectors lose their infectivity within a few hours of removal from the source of infection. This type of virus has been called (Watson and Roberts 1939) non-persistent , for it was observed that the property in which viruses of this type resemble each other, and differ from those viruses whose vectors retain their infectivity for long periods, namely, the persistent viruses. It seems that these differences must lie in the nature of the viruses themselves, for viruses of both types can be transmitted by the same vector. Sugar-beet yellows virus (Petherbridge and Stirrup 1935) seems to be a member of the persistent class, for its vector, Myzus persicae , the same insect as was used in previous work on non-persistent viruses (Watson 1936, 1938; Watson and Roberts 1939), remains infective for several days after removal from the source of infection (Roland 1939). Also it is not transmissible mechanically by any of the usual methods (Quanjer 1934, 1936). The present paper, therefore, describes some studies on the vector-virus relationships of this virus by the methods which have been used previously only on the non-persistent types.

scholarly journals Evaluation of Various Sources of Viral Infection in Strawberry Fields of Quebec, Canada

2019 ◽  
Vol 112 (6) ◽  
pp. 2577-2583
Author(s):  
Phanie Bonneau ◽  
Richard Hogue ◽  
Stéphanie Tellier ◽  
Valérie Fournier
Keyword(s):  
Insect Vectors ◽  
Relative Importance ◽  
Fragaria Ananassa ◽  
Viral Contamination ◽  
Persistent Viruses ◽  
Strawberry Vein Banding Virus ◽  
Before And After ◽  
Fragaria Virginiana ◽  
Wild Strawberry ◽  
Sources Of Contamination

Abstract The decline of cultivated strawberry (Fragaria × ananassa Duchesne ex Rozier; Rosaceae) observed in the province of Quebec, Canada, between 2012 and 2014 was mostly caused by persistent viruses: strawberry mild yellow edge virus (SMYEV) (Potexvirus; Alphaflexiviridae) and strawberry crinkle virus (SCV) (Cytorhabdovirus; Rhabdoviridae); and semi-persistent viruses: strawberry mottle virus (SmoV) (Secoviridae), strawberry vein banding virus (SVBV) (Caulimovirus; Caulimoviridae), and strawberry pallidosis virus (SPaV) (Crinivirus: Closteroviridae) transmitted by insect vectors. The objective of this study was to determine the sources of viral contamination in commercial strawberry fields in Quebec. Specifically, we wished to 1) determine the prevalence of persistent viruses in winged strawberry aphid Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) specimens captured; 2) determine the prevalence of all viruses in wild strawberry Fragaria virginiana Miller plants near commercial plantings; and 3) evaluate the viral contamination of strawberry transplants obtained from nurseries and tested before and after planting in commercial strawberry fields. Results indicated high percentage (38%) of the aphids (n = 205) and high percentage (67%) of F. virginiana patches (n = 12) were infected by strawberry viruses. Ultimately, our results showed a low percentage (5%) of the plants from various nurseries (n = 56) were infected before planting, whereas a third (29%) of the healthy exposed plants in the fields (n = 96) became rapidly infected by insect vectors within a year of having been planted. This study provides significant insights on the relative importance of the various sources of contamination in Quebec strawberry fields: C. fragaefolii versus F. virginiana versus nurseries versus post-nursery infections through exposure to virus-carrying insects.

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