ABSTRACT
The mechanisms of calicivirus attachment and internalization are not well understood, mainly due to the lack of a reliable cell-culture system for most of its members. In this study, rabbit vesivirus (RaV) virions were shown to bind annexin A2 (ANXA2) in a membrane protein fraction from HEK293T cells, using a virus overlay protein-binding assay and matrix-assisted laser desorption/ionization time-of-flight analysis. A monoclonal anti-ANXA2 antibody and small interfering RNA-mediated knockdown of ANXA2 expression in HEK293T cells reduced virus infection significantly, further supporting the role of ANXA2 in RaV attachment and/or internalization.
Subject(s)
Annexin A2/metabolism , Receptors, Virus/metabolism , Vesivirus/physiology , Virus Internalization , Animals , Annexin A2/antagonists & inhibitors , Antibodies, Monoclonal/immunology , Cell Line , Gene Knockdown Techniques , Humans , Protein Binding , Rabbits , Receptors, Virus/antagonists & inhibitorsABSTRACT
The Herpesviridae includes at least eight viral species pathogenic for humans, responsible for a wide variety of clinical symptoms. The lack of an effective vaccine and the moderate to high toxicity of the available synthetic anti-herpes compounds emphasises the need for new inhibitors. Several Phyllanthus genus (Euphorbiaceae) members have been widely used in traditional medicine and their biological properties have been intensely studied. In this study we investigated the in vitro antiviral activity of the Cuban-endemic plant Phyllanthus orbicularis H.B.K. against Herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) reference strains and clinical isolates with different sensitivities to acyclovir. The inhibitory activity on Human cytomegalovirus (HCMV) replication was also investigated. The selectivity indexes (SI) found for Ph. orbicularis aqueous extract ranged from 8.7 to 37.6. Studies on the antiviral mechanisms involved revealed that the drug acted at early stages of herpesvirus replication, possibly by producing a virucidal effect, although further inhibition of intracellular replication events could not be ruled out.
Subject(s)
Antiviral Agents/analysis , Herpesviridae/drug effects , Phyllanthus/chemistry , Plant Extracts/pharmacology , Acyclovir , Animals , Chlorocebus aethiops , Chromatography, Liquid , Drug Evaluation, Preclinical , Drug Resistance, Viral , Herpesviridae Infections/drug therapy , Humans , Phytotherapy , Plant Extracts/therapeutic use , Vero Cells , Virus Replication/drug effectsABSTRACT
Rabbit vesivirus infection induces membrane modifications and accumulation of vesicular structures in the cytoplasm of infected Vero cells. Crude RaV replication complexes (RCs) have been purified and their structural and functional properties have been characterized. We show that calnexin, an ER-resident protein, RaV non-structural proteins 2AB-, 2C-, 3A-, 3B- and 3CD-like as well as viral RNAs co-localize within membranous structures which are able to replicate the endogenous RNA templates. The purified virus factories protected their viral RNA contents from microccocal nuclease degradation and were inaccessible to exogenously added synthetic transcripts. In addition, we have shown that RCs can be used to investigate uridylylation of native endogenous VPg. In contrast to the observation that the virus factories were inaccessible to RNAs, RCs were accessible to added recombinant VPg which was subsequently nucleotidylylated. Nevertheless no elongation of an RNA chain attached to native or recombinant VPg could be demonstrated.
Subject(s)
Kidney/cytology , Kidney/virology , Vesivirus/growth & development , Virus Replication , Animals , Antibodies, Viral/metabolism , Chlorocebus aethiops , Detergents/pharmacology , Fluorescent Antibody Technique, Indirect , Octoxynol , Polyethylene Glycols/pharmacology , RNA, Viral/metabolism , Rabbits , Vero Cells , Vesivirus/drug effects , Viral Proteins/metabolism , Virus Replication/drug effectsABSTRACT
This report describes the isolation, cDNA cloning, complete genome nucleotide sequence, and partial characterization of a new cultivable calicivirus isolated from juvenile feeder European rabbits (Oryctolagus cuniculus) showing symptoms of diarrhea. Absence of neutralization by type-specific neutralizing antibodies for 40 caliciviruses and phylogenetic sequence comparisons of the open reading frame 1-encoded polyprotein with those of other caliciviruses demonstrate that this new calicivirus is a putative novel member of the Vesivirus genus which is closely related to the marine calicivirus subgroup. According to its putative classification, this new virus has been named rabbit vesivirus.
Subject(s)
RNA, Viral/genetics , Rabbits/virology , Vesivirus/isolation & purification , Animals , Base Sequence , Consensus Sequence , DNA, Viral/genetics , Genome, Viral , Molecular Sequence Data , Oligodeoxyribonucleotides/chemistry , Open Reading Frames , Phylogeny , RNA, Viral/chemistry , Vesivirus/classification , Vesivirus/geneticsABSTRACT
Se realizó un estudio farmacognóstico y fitoquímico preliminar de Phyllanthus orbicularis HBK, donde se determinaron inicialmente las características macromorfológicas y micromorfológicas de las hojas y tallos de la especie. Se estandarizó la droga cruda, cuyos valores promedio obtenidos se encontraban dentro del rango permisible, cuando los comparamos con los de drogas oficiales. Se determinó la composición química general de la droga mediante ensayos de tamizaje fitoquímico, y se detectó la presencia de flavonoides, alcaloides, coumarinas, saponinas, aminoácidos, antocianidinas, mucílagos, triterpenos y/o esteroides, sustancias reductoras, taninos pirocatecólicos, principios amargos y astringentes, glicósidos y quinonas. También se cuantificaron algunos de estos metabolitos. Se procedió finalmente, a la extracción y fraccionamiento de flavonoides, obteniéndose fracciones muy simples con la presencia de dichos compuestos; además, se detecta rutina y quercetina, así como 2 compuestos cromatográficamente puros, que según los análisis efectuados se sospecha que sean flavonoides
Subject(s)
Plant Leaves , Plant Stems , Plants, MedicinalABSTRACT
Se realizó un estudio farmacognóstico y fitoquímico preliminar de Phyllanthus orbicularis HBK, donde se determinaron inicialmente las características macromorfológicas y micromorfológicas de las hojas y tallos de la especie. Se estandarizó la droga cruda, cuyos valores promedio obtenidos se encontraban dentro del rango permisible, cuando los comparamos con los de drogas oficiales. Se determinó la composición química general de la droga mediante ensayos de tamizaje fitoquímico, y se detectó la presencia de flavonoides, alcaloides, coumarinas, saponinas, aminoácidos, antocianidinas, mucílagos, triterpenos y/o esteroides, sustancias reductoras, taninos pirocatecólicos, principios amargos y astringentes, glicósidos y quinonas. También se cuantificaron algunos de estos metabolitos. Se procedió finalmente, a la extracción y fraccionamiento de flavonoides, obteniéndose fracciones muy simples con la presencia de dichos compuestos; además, se detecta rutina y quercetina, así como 2 compuestos cromatográficamente puros, que según los análisis efectuados se sospecha que sean flavonoides (AU)
Subject(s)
Plants, Medicinal , Plant Stems , Plant LeavesABSTRACT
Se obtienen varias muestras durante un brote epizoótico en palomas Columba livia domestica ocurrido a finales de 1970 en la colina universitaria de la Ciudad de La Habana de las cuales se lograron 2 aislamientos virales. En el presente trabajo se describe la metodología seguido para la identificación de uno de estos aislamientos, que fue identificado como una cepa del virus de la encefalomelitis equina del este (EEE). Se discuten varios aspectos ecológicos relacionados con el hecho de que otro aislamiento obtenido de las muestras del mismo brote fue identificado anteriormente como encefalitis equina del oeste (EEO)(AU)
