scholarly journals Long-Term Evolution of the Luteoviridae: Time Scale and Mode of Virus Speciation

2010 ◽  
Vol 84 (12) ◽  
pp. 6177-6187 ◽  
Author(s):  
Israel Pagán ◽  
Edward C. Holmes
Keyword(s):  
Time Scale ◽  
Rna Viruses ◽  
Evolutionary Processes ◽  
Plant Host ◽  
Selection Pressures ◽  
The Family ◽  
Clock Analysis ◽  
Molecular Clock Analysis ◽  
Recombination Breakpoints

ABSTRACT Despite their importance as agents of emerging disease, the time scale and evolutionary processes that shape the appearance of new viral species are largely unknown. To address these issues, we analyzed intra- and interspecific evolutionary processes in the Luteoviridae family of plant RNA viruses. Using the coat protein gene of 12 members of the family, we determined their phylogenetic relationships, rates of nucleotide substitution, times to common ancestry, and patterns of speciation. An associated multigene analysis enabled us to infer the nature of selection pressures and the genomic distribution of recombination events. Although rates of evolutionary change and selection pressures varied among genes and species and were lower in some overlapping gene regions, all fell within the range of those seen in animal RNA viruses. Recombination breakpoints were commonly observed at gene boundaries but less so within genes. Our molecular clock analysis suggested that the origin of the currently circulating Luteoviridae species occurred within the last 4 millennia, with intraspecific genetic diversity arising within the last few hundred years. Speciation within the Luteoviridae may therefore be associated with the expansion of agricultural systems. Finally, our phylogenetic analysis suggested that viral speciation events tended to occur within the same plant host species and country of origin, as expected if speciation is largely sympatric, rather than allopatric, in nature.

scholarly journals Selection pressures in the capsid genes of plant RNA viruses reflect mode of transmission

2004 ◽  
Vol 85 (10) ◽  
pp. 3149-3157 ◽  
Author(s):  
Elizabeth R. Chare ◽  
Edward C. Holmes
Keyword(s):  
Rna Viruses ◽  
Purifying Selection ◽  
Plant Viruses ◽  
Capsid Proteins ◽  
Plant Host ◽  
Selection Pressures ◽  
Cellular Receptors ◽  
Selective Constraints ◽  
Modes Of Transmission ◽  
Vector Borne

To determine the selection pressures faced by RNA viruses of plants, patterns of nonsynonymous (d N) and synonymous (d S) substitution in the capsid genes of 36 viruses with differing modes of transmission were analysed. This analysis provided strong evidence that the capsid proteins of vector-borne plant viruses are subject to greater purifying selection on amino acid change than those viruses transmitted by other routes and that virus–vector interactions impose greater selective constraints than those between virus and plant host. This could be explained by specific interactions between capsid proteins and cellular receptors in the insect vectors that are necessary for successful transmission. However, contrary to initial expectations based on phylogenetic relatedness, vector-borne plant viruses are subject to weaker selective constraints than vector-borne animal viruses. The results suggest that the greater complexity involved in the transmission of circulative animal viruses compared with non-circulative plant viruses results in more intense purifying selection.

The long-term instability of the new generation hydrogen masers

2020 ◽  
pp. 35-38
Author(s):  
S.I. Donchenko ◽  
I.Y. Blinov ◽  
I.B. Norets ◽  
Y.F. Smirnov ◽  
A.A. Belyaev ◽  
...  
Keyword(s):  
Time Scale ◽  
Frequency Difference ◽  
Clock Frequency ◽  
Quantum Frequency ◽  
Frequency Standards ◽  
Quantum Frequency Standards ◽  
New Generation ◽  
Atomic Time

The latest changes in the algorithm for the formation of the international atomic time scale TAI are reported in terms of estimating the weights of the clocks involved in the formation of TAI. Studies of the characteristics of the long-term instability of new-generation hydrogen masers based on processing the results of the clock frequency difference with respect to TAI are performed. It has been confirmed that at present, new-generation hydrogen masers show significantly less long-term instability in comparison with quantum frequency standards ofsimilar and other types.

Evaluation of the Laxative activity of Saponin Enriched Hydroethanolic Pericarp extract of Sapindus emarginatus in Animal models

2020 ◽  
Vol 16 ◽  
Author(s):  
Lalitha Vivekanandan ◽  
Roxanne Gekonge Mandere ◽  
Sivakumar Thangavel
Keyword(s):  
Animal Models ◽  
Gravimetric Analysis ◽  
Triterpene Saponins ◽  
Laxative Effect ◽  
Saponin Content ◽  
The Family ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Efficacious Drug

Background: Constipation is a common, predominant, chronic gastrointestinal functional disorder. The drugs available to treat constipation are limited because of their side effects in long term use. So we need of efficacious drug to treat constipation. Sapindus emarginatus Vahl belongs to the family Sapindaceae, commonly known as soapnut. Traditionally used for the antipruritic, antifertility, constipation, and anti-inflammatory agents. Objective: The present study was undertaken to evaluate the laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus (HESE) in animal models. Methods: The saponin content in extract was measured by gravimetric analysis. The laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus is evaluated by the weight of feces matter, charcoal meal hyperperistalsis test, and loperamide induced constipation model. Results: The saponin content of the soapnut pericarp was 13.48 % and the extract was found to be 11.92 %. The results obtained from these models showed a significant dose-dependent increase in fecal weight, peristalsis index, and moisture content compared to control animals. Conclusion: The present study concluded that the oral administration of HESE showed a significant laxative activity by using different animal models. The presence of triterpene saponins is responsible for this activity. Further studies are needed to confirm their mechanism behind the laxative effect. The administration of extract was found to be a valid candidate in constipation therapy.

Redescription and relationships of Pseudothilmanus Pic (Coleoptera: Rhagophthalmidae)—a long-term neglected glow-worm beetle genus from the Himalayas

Zootaxa ◽  
2011 ◽  
Vol 2794 (1) ◽  
pp. 57 ◽  
Author(s):  
ROBIN KUNDRATA ◽  
LADISLAV BOCAK
Keyword(s):  
Morphological Divergence ◽  
Diagnostic Characters ◽  
The Family

Pseudothilmanus Pic, 1918 is redescribed and two species, P. alatus Pic, 1918 and P. marginatus Pic, 1918, are placed in the genus. The subgenus Drilothilmanus Pic, 1918 is synonymized with the nominotypical genus on the basis of low morphological divergence and redundancy in classification. Pseudothilmanus is newly classified in the family Rhagophthalmidae, in contrast to the original placement in Drilidae. Diagnostic characters for Pseudothilmanus and both species placed within the genus are illustrated.

scholarly journals Are Family Firms More Levered? An Analysis of Family and Non-Family Firms

SAGE Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215824402110223
Author(s):  
Jahanzaib Haider ◽  
Abdul Qayyum ◽  
Zalina Zainudin
Keyword(s):  
Family Firms ◽  
East Asian ◽  
Ordinary Least Squares ◽  
Maturity Structure ◽  
The Family ◽  
Asian Economies ◽  
The Board Of Directors ◽  
East Asian Economies ◽  
Combined Data

This study analyzes the leverage policies of the family and non-family firms of eight East Asian Economies (Hong Kong, Indonesia, Japan, Korea, Malaysia, Philippines, Singapore, and Taiwan) by using combined data of 690 family and non-family firms with 3,224 firm–years over the period 2006–2010. This study has used an ordinary least squares (OLS) regression for analyzing the data for the first question, while for the second question, logit regression has been used as the dependent variable (a binary variable). Prior research on family and non-family firms has revealed that family firms issue less (high) debt than non-family firms. Our analysis on a sample of East Asian Economies discloses that family firms have significantly different leverage levels than non-family firms, but their signs are not consistent. On the contrary, when the owner works as CEO/Chairman or member of the Board of Directors, then the family firms issue less debt than the non-family firms. Besides that, this study adds a new question that has not been addressed in the prior studies. The new question has focused on the speed of leverage adjustment. It is found that family firms and non-family firms regarding their debt maturity structure (short-term debt and long-term debt), the speed of leverage adjustments, and their decision to issue securities (i.e., debt vs. equity) are not significantly different. This study concluded that though family firms have a strong influence on each economy, but in South-East Asian countries, leverage policies of the family firms are not much different than that of non-family firms.

scholarly journals Genomics and epidemiology of the P.1 SARS-CoV-2 lineage in Manaus, Brazil

Science ◽  
2021 ◽  
pp. eabh2644 ◽  
Author(s):  
Nuno R. Faria ◽  
Thomas A. Mellan ◽  
Charles Whittaker ◽  
Ingra M. Claro ◽  
Darlan da S. Candido ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Genome Sequencing ◽  
Immune Evasion ◽  
Molecular Clock ◽  
Spike Protein ◽  
Dynamical Model ◽  
Mortality Data ◽  
Clock Analysis ◽  
Protection Against Infection ◽  
Molecular Clock Analysis

Cases of SARS-CoV-2 infection in Manaus, Brazil, resurged in late 2020, despite previously high levels of infection. Genome sequencing of viruses sampled in Manaus between November 2020 and January 2021 revealed the emergence and circulation of a novel SARS-CoV-2 variant of concern. Lineage P.1, acquired 17 mutations, including a trio in the spike protein (K417T, E484K and N501Y) associated with increased binding to the human ACE2 receptor. Molecular clock analysis shows that P.1 emergence occurred around mid-November 2020 and was preceded by a period of faster molecular evolution. Using a two-category dynamical model that integrates genomic and mortality data, we estimate that P.1 may be 1.7–2.4-fold more transmissible, and that previous (non-P.1) infection provides 54–79% of the protection against infection with P.1 that it provides against non-P.1 lineages. Enhanced global genomic surveillance of variants of concern, which may exhibit increased transmissibility and/or immune evasion, is critical to accelerate pandemic responsiveness.

scholarly journals HGG-47. DECREASED GROWTH VELOCITY WITH LONG TERM USE OF BRAFV600e AND MEK INHIBITION IN A PATIENT WITH ANAPLASTIC GANGLIOGLIOMA

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii352-iii352
Author(s):  
Hung Tran ◽  
Robert Cooper
Keyword(s):  
Growth Velocity ◽  
Direct Result ◽  
Chromosomal Microarray ◽  
Mek Inhibition ◽  
Follow Up Study ◽  
The Family ◽  
The Relationship

Abstract PURPOSE To describe decreased growth velocity with long term use of BRAFV600e and MEK inhibition in a patient with anaplastic ganglioglioma. RESULTS 4-year-old patient was found to have a 6 x 4.6 x 5 cm mass in the hypothalamus. Pathology consistent with anaplastic ganglioglioma and chromosomal microarray revealed a BRAFV600e mutation. Patient started on dabrafenib and trametinib and tumor decreased 85% after 3 months. She is stable without significant toxicities 39 months on therapy, and is now 8 years old. Patient had been growing at the 25% for weight and 12% for height but is now 65% for weight and 0.5% for height. It is difficult to tease out the relationship between the tumor, the location of the tumor, and the BRAF and MEK inhibitors and their effect on growth. Discussions with the family and endocrinology are ongoing but being <1% for height will lead to decrease in quality of life. CONCLUSIONS Further follow-up study is needed to determine if this is truly a long-term toxicity, or if this may just be a direct result of the location of the tumor. Would supplementation with growth hormone in this patient lead to losing control of a high grade tumor, or would it simply replace a hormone that is not produced?

scholarly journals Ensemble Pulsar Time Study by Pulsar Timing Observations

2004 ◽  
Vol 218 ◽  
pp. 439-440
Author(s):  
Tinggao Yang ◽  
Guangren Ni
Keyword(s):  
Time Scale ◽  
Wavelet Decomposition ◽  
Time Study ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Pulsar Time ◽  
Pulsar Timing ◽  
Timing Data ◽  
Gravitational Wave Background

Long term timing of multiple millisecond pulsars can contribute to the study of an ensemble pulsar time scale PTens. A wavelet decomposition algorithm (WDA) was applied to define a PTens using the available millisecond pulsar timing datA. The PTens obtained from WDA is more stable than those resulting from other algorithms. The Chinese 50 m radio telescope is specially designed for PTens study and detection of gravitational wave background via millisecond pulsars timing observations. A scheme for multiple millisecond pulsar timing and ensemble pulsar time study is discussed in some detail.

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