Molecular dynamics simulations of Zika virus NS3 helicase: Insights into RNA binding site activity.

America is still suffering with the outbreak of Zika virus (ZIKV) infection. Congenital ZIKV syndrome has already caused a public health emergency of international concern. However, there are still no vaccines to prevent or drugs to treat the infection caused by ZIKV. The ZIKV NS3 helicase (NS3h) protein is a promising target for drug discovery due to its essential role in viral genome replication. NS3h unwinds the viral RNA to enable the replication of the viral genome by the NS5 protein. NS3h contains two important binding sites: the NTPase binding site and the RNA binding site. Here, we used molecular dynamics (MD) simulations to study the molecular behavior of ZIKV NS3h in the presence and absence of ssRNA and the potential implications for NS3h activity and inhibition. Although there is conformational variability and poor electron densities of the RNA binding loop in various apo flaviviruses NS3h crystallographic structures, the MD trajectories of NS3h-ssRNA demonstrated that the RNA binding loop becomes more stable when NS3h is occupied by RNA. Our results suggest that the presence of RNA generates important interactions with the RNA binding loop, and these interactions stabilize the loop sufficiently that it remains in a closed conformation. This closed conformation likely keeps the ssRNA bound to the protein for a sufficient duration to enable the unwinding/replication activities of NS3h to occur. In addition, conformational changes of this RNA binding loop can change the nature and location of the optimal ligand binding site, according to ligand binding site prediction results. These are important findings to help guide the design and discovery of new inhibitors of NS3h as promising compounds to treat the ZIKV infection.

Intravenous lidocaine for postmastectomy pain treatment: randomized, blind, placebo controlled clinical trial / Lidocaína intravenosa no tratamento da dor pós-mastectomia: ensaio clínico aleatório encoberto placebo controlado / Lidocaína intravenosa en el tratamiento del dolor posmastectomía: ensayo clínico aleatorizado, encubierto, placebo controlado

BACKGROUND AND OBJECTIVE: Postoperative pain treatment in mastectomy remains a major challenge despite the multimodal approach. The aim of this study was to investigate the analgesic effect of intravenous lidocaine in patients undergoing mastectomy, as well as the postoperative consumption of opioids. METHODS: After approval by the Human Research Ethics Committee of the Instituto de Medicina Integral Prof. Fernando Figueira in Recife, Pernambuco, a randomized, blind, controlled trial was conducted with intravenous lidocaine at a dose of 3 mg/kg infused over 1 h in 45 women undergoing mastectomy under general anesthesia. One patient from placebo group was. RESULTS: Groups were similar in age, body mass index, type of surgery, and postoperative need for opioids. Two of 22 patients in lidocaine group and three of 22 patients in placebo group requested opioid (p = 0.50). Pain on awakening was identified in 4/22 of lidocaine group and 5/22 of placebo group (p = 0.50); in the post-anesthetic recovery room in 14/22 and 12/22 (p = 0.37) of lidocaine and placebo groups, respectively. Pain evaluation 24 h after surgery showed that 2/22 and 3/22 patients (p = 0.50) of lidocaine and placebo groups, respectively, complained of pain. CONCLUSION: Intravenous lidocaine at a dose of 3 mg/kg administered over a period of an hour during mastectomy did not promote additional analgesia compared to placebo in the first 24 h, and has not decreased opioid consumption. However, a beneficial effect of intravenous lidocaine in selected and/or other therapeutic regimens patients cannot be ruled out. .

JUSTIFICATIVA E OBJETIVO: O tratamento da dor pós-operatória em mastectomia continua sendo um grande desafio apesar da abordagem multimodal. O objetivo deste estudo foi investigar o efeito analgésico da lidocaína intravenosa em pacientes submetidas a mastectomia, como também, o consumo de opioide pós-operatório. MÉTODOS: Após aprovação pelo comitê de ética e pesquisa em seres humanos do Instituto de Medicina Integral Prof. Fernando Figueira em Recife - Pernambuco foi realizado ensaio clínico aleatório encoberto placebo controlado com lidocaína intravenosa na dose de 3 mg/kg infundida em uma hora, em 45 mulheres submetidas a mastectomia sob anestesia geral. Excluída uma paciente do grupo placebo. RESULTADOS: Os grupos foram semelhantes quanto à idade, índice de massa corpórea, tipo de intervenção cirúrgica e necessidade de opioide no pós-operatório. Solicitaram opioide 2/22 pacientes nos grupos da lidocaína e 3/22 placebo (p = 0,50). Identificada a dor ao despertar em 4/22 no grupo lidocaína e 5/22 (p = 0,50) no grupo placebo; na sala de recuperação pós-anestésica em 14/22 e 12/22 (p = 0,37) nos grupos lidocaína e placebo respectivamente. Ao avaliar a dor 24 horas após o procedimento cirúrgico 3/22 e 2/22 (p = 0,50) das pacientes relataram dor em ambos os grupos respectivamente. CONCLUSÃO: A lidocaína intravenosa na dose de 3mg/kg administrada em um período de uma hora no transoperatório de mastectomia não promoveu analgesia adicional em relação ao grupo placebo nas primeiras 24 horas e não diminuiu o consumo de opioide. Contudo, um efeito benéfico da lidocaína intravenosa em pacientes selecionadas e/ou em outros regimes terapêuticos não pode ser descartado. .

JUSTIFICACIÓN Y OBJETIVO: El tratamiento del dolor postoperatorio en la mastectomía continúa siendo un gran reto a pesar del abordaje multimodal. El objetivo de este estudio fue investigar el efecto analgésico de la lidocaína intravenosa en pacientes sometidas a mastectomía, así como el consumo postoperatorio de opiáceos. MÉTODOS: Después de la aprobación por el Comité de Ética e Investigación en seres humanos del Instituto de Medicina Integral Prof. Fernando Figueira, en Recife, Pernambuco, se realizó un ensayo clínico aleatorizado, encubierto, placebo controlado con lidocaína intravenosa en una dosis de 3 mg/kg infundida en una hora, en 45 mujeres sometidas a mastectomía bajo anestesia general. Una paciente del grupo placebo fue excluida. RESULTADOS: Los grupos fueron similares en cuanto a la edad, índice de masa corporal, tipo de intervención quirúrgica y necesidad de opiáceos en el postoperatorio. Solicitaron opiáceos 2/22 pacientes en los grupos de la lidocaína y 3/22 placebo (p = 0,50). Fue identificado el dolor al despertar en 4/22 en el grupo lidocaína y 5/22 (p = 0,50) en el grupo placebo; en la sala de recuperación postanestésica en 14/22 y 12/22 (p = 0,37) en los grupos lidocaína y placebo, respectivamente. Al calcular el dolor 24 h después del procedimiento quirúrgico 3/22 y 2/22 (p = 0,50) de las pacientes relataron dolor en ambos grupos respectivamente. CONCLUSIÓN: La lidocaína intravenosa en una dosis de 3 mg/kg administrada en un período de una hora en el transoperatorio de mastectomía no generó analgesia adicional con relación al grupo placebo en las primeras 24 h y no disminuyó el consumo de opiáceos. Sin embargo, no puede ser descartado un efecto beneficioso de la lidocaína intravenosa en pacientes seleccionadas y/o en otros regímenes terapéuticos. .

Mycovirus in Pseudocercospora griseola, the causal agent of angular leaf spot in common bean.

Pseudocercospora griseola (Sacc.) Crous & Braun is a widespread fungal phytopathogen that is responsible for angular leaf spot in the common bean (Phaseolus vulgaris L.). A number of fungal phytopathogens have been shown to harbour mycoviruses, and this possibility was investigated in populations of Pseudocercospora griseola. The total nucleic acid extracts of 61 fungal isolates were subjected to agarose gel electrophoresis. Small fragments (800-4800 bp) could be identified in 42 of the samples. The presence of dsRNA in isolate Ig838 was confirmed by treatment of total nucleic acid with DNase, RNase A, and nuclease S1. Transmission electron microscopy revealed the presence of viral-like particles 40 nm in diameter in the mycelia of 2 fungal isolates, namely 29-3 and Ig838. The transmission of dsRNA by means of conidia was 100% for isolate 29-3, but there was loss of 1-6 fragments of dsRNA in monosporic colonies of isolate Ig848. Cycloheximide treatment failed to inhibit the mycovirus in isolate 29-3, but proved efficient in the elimination of the 2.2, 2.0, 1.8, 1.2 and 1.0 kb fragments in 2 colonies of isolate Ig848. The occurrence of a mycovirus in Pseudocercospora griseola was demonstrated for the first time in the present study.

Nucleic acid binding properties and intermediates of HCV core protein multimerization in Pichia pastoris.

Little is known about the in vivo assembly pathway or structure of the hepatitis C virus nucleocapsid. In this work the intermediates of HCcAg multimerization in Pichia pastoris cells and the nucleic acid binding properties of structured nucleocapsid-like particles (NLPs) were studied. Extensive cross-linking was observed for HCcAg after glutaraldehyde treatment. Data suggest that HCcAg exists in dimeric forms probably representing P21-P21, P21-P23, and P23-P23 dimers. In addition, the presence of HCcAg species that might represent trimers and multimers was observed. After sucrose equilibrium density gradient purification and nuclease digestion, NLPs were shown to contain both RNA and DNA molecules. Finally, the analysis by electron microscopy indicated that native NLPs were resistant to nuclease treatment. These results indicated that HCcAg assembles through dimers, trimers, and multimers' intermediates into capsids in P. pastoris cells. Assembly of NLPs in its natural environment might confer stability to these particles by adopting a compact structure.

Intracellular localisation of dengue-2 RNA in mosquito cell culture using electron microscopic in situ hybridisation.

Non-isotopic in situ hybridisation was used at the electron microscope level to determine the localisation of viral RNA in dengue-2 infected mosquito cells at 14, 24, 48 and 72 h post-infection. In situ hybridisation was carried out on sections of dengue-2 infected mosquito cells using a digoxigenin-labelled DNA probe to the envelope protein gene sequence of the virus. Viral RNA was consistently localised over the rough endoplasmic reticulum and the virus-induced smooth membrane structures which form within the endoplasmic reticulum. During the later stages of infection electron-dense areas were observed to develop in close proximity to the smooth membrane structures. Electron microscopic in situ hybridisation showed that these denser areas contained both viral RNA and virus particles. Our results show that in dengue-2 infected mosquito cells the smooth membrane structures are an important site for the concentration of dengue viral RNA and its possible subsequent encapsidation into virus particles.

The 3' end termini of the Tacaribe arenavirus subgenomic RNAs.

Tacaribe virus (TV), a member of the Arenaviridae family, contains two single-stranded RNA genome segments called S and L. Two proteins, in an ambisense coding strategy, are encoded in both the S RNA and the L RNA. The 3' ends of the TV four putative mRNAs have been characterized using S1 nuclease mapping. The experiments revealed that the transcripts terminate within the intergenic region in each RNA segment. No special sequences that might function as termination signals were evident. The 3' end sequences of the four putative mRNAs can be predicted to adopt GC-rich stable hairpin configurations (delta G greater than or equal to -25 kcal). These observations suggest that the transcript structure rather than particular sequences might be the signal involved in the termination of arenavirus transcription.

Comparaçäo dos testes de aglutinaçäo do látex, microscopia eletrônica e eletroforese em gel de poliacrilamida do RNA viral na detecçäo de rotavírus em fezes diarréicas de crianças / Comparative study of the latex agglutination test, electron microscopy and polyacrylamide gel eletrophorresis for the detection of human rotavirus

171 amostras fecais de crianças hospitalizadas com diarréia aguda foram testadas quanto a presença de rotavírus através de microscopia eletrônica (ME), eletroforese em gel de poliacrilamida (EGPA) (com e sem extraçäo do RNA viral) e agolutinaçäo do látex (AL) (Slidex Rota - Kit 2). Para a prova do látex foi feita uma reduçäo das quantidades dos reagentes. Houve concordância dos resultados de 91,8%. A extraçäo do RNA viral possibilitou a detecçäo de mais amostras positivas pela eletroforese. A sensibilidade da ME e EGPA foi de 62,5%. A prova do látex foi mais sensível que as demais (75%) e a reduçäo das quantidades dos reagentes parece näo ter afetado a performance do teste

In vitro synthesis of infectious venezuelan equine encephalitis virus RNA from a cDNA clone: analysis of a viable deletion mutant.

A molecular clone of Venezuelan equine encephalitis virus (VEE) was constructed from four cDNAs that were synthesized using the viral RNA genome as template. Together, these cDNAs are believed to represent all but the nine 5'-terminal nucleotides of the VEE genome sequence. A T7 promoter, followed by a single intervening G residue, and the exact 5'-terminus of VEE were added to the 5'-most clone using in vitro mutagenesis. Appropriate restriction fragments isolated from the cloned cDNAs were joined to form a candidate full-length VEE cDNA clone. RNA transcripts synthesized in vitro from the cDNA clone were able to initiate a productive infection in DEAE-dextran-treated chicken embryo fibroblasts (CEF). VEE antigens were demonstrated in RNA-transfected cells, and supernatants from transfected cultures contained infectious virus particles. The candidate full-length cDNA clone lacked 102 nucleotides of the VEE genome sequence. The deletion, which also was present in the genomes of progeny virions derived from the clone, did not appear to affect growth in cultured CEF, baby hamster kidney cells, or Vero cells. The site of the deletion was mapped to the 3'-end of the nsP3 gene by comparison to other alphavirus sequences. In this region, the VEE genome sequence includes two tandem 102-nucleotide repeats which can be arranged in a stable stem and loop structure. The sequence remaining in the deleted clone retains one copy of the duplicated sequence and, in addition, faithfully preserves a portion of the predicted stem.