@article{yamamoto_blackburn_goshe_brown_migoswski_campanhon_moreira_ferreira_soares_2023, title={Tizoxanide Antiviral Activity on Dengue Virus Replication}, volume={15}, ISSN={["1999-4915"]}, DOI={10.3390/v15030696}, abstractNote={Dengue virus is an important circulating arbovirus in Brazil responsible for high morbidity and mortality worldwide, representing a huge economic and social burden, in addition to affecting public health. In this study, the biological activity, toxicity, and antiviral activity against dengue virus type 2 (DENV-2) of tizoxanide (TIZ) was evaluated in Vero cell culture. TIZ has a broad spectrum of action in inhibiting different pathogens, including bacteria, protozoa, and viruses. Cells were infected for 1 h with DENV-2 and then treated for 24 h with different concentrations of the drug. The quantification of viral production indicated the antiviral activity of TIZ. The protein profiles in infected Vero cells treated and not treated with TIZ were analyzed using the label-free quantitative proteomic approach. TIZ was able to inhibit virus replication mainly intracellularly after DENV-2 penetration and before the complete replication of the viral genome. Additionally, the study of the protein profile of infected not-treated and infected-treated Vero cells showed that TIZ interferes with cellular processes such as intracellular trafficking and vesicle-mediated transport and post-translational modifications when added after infection. Our results also point to the activation of immune response genes that would eventually lead to a decrease of DENV-2 production. TIZ is a promising therapeutic molecule for the treatment of DENV-2 infections.}, number={3}, journal={VIRUSES-BASEL}, author={Yamamoto, Kristie A. and Blackburn, Kevin and Goshe, Michael B. and Brown, Dennis T. and Migoswski, Edimilson and Campanhon, Isabele B. and Moreira, Monica F. and Ferreira, Davis F. and Soares, Marcia R.}, year={2023}, month={Mar} }
 @article{goncalves tiburcio_macrae_peixoto_costa rachid_passos mansoldo_alviano_alviano_ferreira_venancio_ferreira_et al._2021, title={Sulphate-reducing bacterial community structure from produced water of the Periquito and Galo de Campina onshore oilfields in Brazil}, volume={11}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-021-99196-x}, abstractNote={Abstract Sulphate-reducing bacteria (SRB) cause fouling, souring, corrosion and produce H 2 S during oil and gas production. Produced water obtained from Periquito (PQO) and Galo de Campina (GC) onshore oilfields in Brazil was investigated for SRB. Produced water with Postgate B, Postgate C and Baars media was incubated anaerobically for 20 days. DNA was extracted, 16S rDNA PCR amplified and fragments were sequenced using Illumina TruSeq. 4.2 million sequence reads were analysed and deposited at NCBI SAR accession number SRP149784. No significant differences in microbial community composition could be attributed to the different media but significant differences in the SRB were observed between the two oil fields. The dominant bacterial orders detected from both oilfields were Desulfovibrionales, Pseudomonadales and Enterobacteriales. The genus Pseudomonas was found predominantly in the GC oilfield and Pleomorphominas and Shewanella were features of the PQO oilfield. 11% and 7.6% of the sequences at GC and PQO were not classified at the genus level but could be partially identified at the order level. Relative abundances changed for Desulfovibrio from 29.8% at PQO to 16.1% at GC. Clostridium varied from 2.8% at PQO and 2.4% at GC. These data provide the first description of SRB from onshore produced water in Brazil and reinforce the importance of Desulfovibrionales, Pseudomonadales, and Enterobacteriales in produced water globally. Identifying potentially harmful microbes is an important first step in developing microbial solutions that prevent their proliferation.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Goncalves Tiburcio, Samyra Raquel and Macrae, Andrew and Peixoto, Raquel Silva and Costa Rachid, Caio Tavora and Passos Mansoldo, Felipe Raposo and Alviano, Daniela Sales and Alviano, Celuta Sales and Ferreira, Davis Fernandes and Venancio, Fabricio de Queiroz and Ferreira, Doneivan Fernandes and et al.}, year={2021}, month={Oct} }
 @article{salles_ferreira meneses_caldas_sa-guimaraes_oliveira_ventura_azevedo_kuster_soares_ferreira_2021, title={Virucidal and antiviral activities of pomegranate (Punica granatum) extract against the mosquito-borne Mayaro virus}, volume={14}, ISSN={["1756-3305"]}, DOI={10.1186/s13071-021-04955-4}, abstractNote={The arthropod-borne Mayaro virus (MAYV) causes "Mayaro fever," a disease of medical significance, primarily affecting individuals in permanent contact with forested areas in tropical South America. Recently, MAYV has attracted attention due to its likely urbanization. There are currently no licensed drugs against most mosquito-transmitted viruses. Punica granatum (pomegranate) fruits cultivated in Brazil have been subjected to phytochemical investigation for the identification and isolation of antiviral compounds. In the present study, we explored the antiviral activity of pomegranate extracts in Vero cells infected with Mayaro virus.The ethanol extract and punicalagin of pomegranate were extracted solely from the shell and purified by chromatographic fractionation, and were chemically identified using spectroscopic techniques. The cytotoxicity of the purified compounds was measured by the dye uptake assay, while their antiviral activity was evaluated by a virus yield inhibition assay.Pomegranate ethanol extract (CC50 = 588.9, IC50 = 12.3) and a fraction containing punicalagin as major compound (CC50 = 441.5, IC50 = 28.2) were shown to have antiviral activity (SI 49 and 16, respectively) against Mayaro virus, an alphavirus. Immunofluorescence analysis showed the virucidal effect of pomegranate extract, and transmission electron microscopy (TEM) revealed damage in viral particles treated with this extract.The P. granatum extract is a promising source of antiviral compounds against the alphavirus MAYV and represents an excellent candidate for future studies with other enveloped RNA viruses.}, number={1}, journal={PARASITES & VECTORS}, author={Salles, Tiago Souza and Ferreira Meneses, Marcelo Damiao and Caldas, Lucio Ayres and Sa-Guimaraes, Thayane Encarnacao and Oliveira, Danielle M. and Ventura, Jose A. and Azevedo, Renata Campos and Kuster, Ricardo M. and Soares, Marcia Regina and Ferreira, Davis Fernandes}, year={2021}, month={Sep} }
 @misc{mello_domingos_ferreira_ribeiro_ribeiro_rodrigues_souza_2020, title={Antiviral Drug Discovery and Development for Mayaro Fever - What do we have so far?}, volume={20}, ISSN={["1875-5607"]}, DOI={10.2174/1389557520666200316160425}, abstractNote={Tropical infectious diseases cause millions of deaths every year in developing countries with about half of the world population living at risk. Mayaro virus (MAYV) is an emerging arbovirus that causes Mayaro fever, which is characterized by fever, headache, diarrhea, arthralgia and rash. These symptoms can be clinically indistinguishable from other arboviruses, such as Dengue, Zika and Chikungunya, which makes the diagnosis and treatment of the disease more difficult. Though, Mayaro virus is a potential candidate to cause large-scale epidemics on the scale of ZIKV and CHIKV. Despite this, there is no licensed vaccine or antiviral for the treatment of Mayaro fever and for most arboviruses, so the design and development of candidates for antiviral drugs are urgently needed. In this context, this mini review aims to provide an overview towards studies of anti-MAYV derivatives and highlight the importance of the discovery and development of promising drug candidates for Mayaro fever.}, number={10}, journal={MINI-REVIEWS IN MEDICINAL CHEMISTRY}, author={Mello, Marcos V. P. and Domingos, Thaisa F. S. and Ferreira, Davis F. and Ribeiro, Mariana M. J. and Ribeiro, Thayssa P. and Rodrigues, Carlos R. and Souza, Alessandra M. T.}, year={2020}, pages={921–928} }
 @article{yamamoto_blackburn_migowski_goshe_brown_ferreira_soares_2020, title={Quantitative proteomic analysis of the tizoxanide effect in vero cells}, volume={10}, ISSN={["2045-2322"]}, DOI={10.1038/s41598-020-71634-2}, abstractNote={Nitazoxanide (NTZ) is effective against helminths and numerous microorganisms, including bacteria and viruses. In vivo, NTZ is metabolized into Tizoxanide (TIZ), which is the active circulating metabolite. With the emergence of SARS-Cov-2 as a Pandemic agent, NTZ became one of the molecules already approved for human use to engage clinical trials, due to results in vitro showing that NTZ was highly effective against the SARS-Cov-2, agent of COVID-19. There are currently several ongoing clinical trials mainly in the USA and Brazil involving NTZ due not only to the in vitro results, but also for its long-known safety. Here, we study the response of Vero cells to TIZ treatment and unveil possible mechanisms for its antimicrobial effect, using a label-free proteomic approach (LC/MS/MS) analysis to compare the proteomic profile between untreated- and TIZ-treated cells. Fifteen differentially expressed proteins were observed related to various biological processes, including translation, intracellular trafficking, RNA processing and modification, and signal transduction. The broad antimicrobial range of TIZ points towards its overall effect in lowering cell metabolism and RNA processing and modification. The decreased levels of FASN, HNRNPH and HNRNPK with the treatment appear to be important for antiviral activity.}, number={1}, journal={SCIENTIFIC REPORTS}, author={Yamamoto, K. A. and Blackburn, K. and Migowski, E. and Goshe, M. B. and Brown, D. T. and Ferreira, D. F. and Soares, M. R.}, year={2020}, month={Sep} }
 @article{azevedo_cardoso_caldas_vieira werneck_cohen_yamamoto_silva meira_meneses_erthal_sa_et al._2020, title={The impact of Zika virus infection on human semen: a case study}, volume={15}, ISSN={["1746-0808"]}, DOI={10.2217/fvl-2019-0159}, abstractNote={The outbreak of Zika virus (ZIKV) in Brazil and in many countries was marked by the occurrences of fetal malformations and neurological effects upon infection of pregnant women. Like other members of the Flaviviridae family, ZIKV in semen is infectious and sexually transmitted. Viral persistence in the male genital tract is unresolved and still needs further understanding. A regular semen donor was followed from the acute phase of ZIKV infection, up to 8 months after ZIKV in his body fluids became undetected. Immunofluorescence assay was performed in semen samples before and after the infection. A significant decrease in sperm concentration and in the percentage of progressive motility of sperm was observed. The methodology adopted for clearance of sexually transmitted viruses decreased virus load, but the complete clearance of ZIKV from semen was not achieved.}, number={1}, journal={FUTURE VIROLOGY}, author={Azevedo, Renata Campos and Cardoso, Maria Cecilia A. and Caldas, Lucio Ayres and Vieira Werneck, Caio Luis and Cohen, Cristiane Napoleao and Yamamoto, Kristie Aimi and Silva Meira, Guilherme Louzada and Meneses, Marcelo Damiao and Erthal, Maria Cecilia and Sa, Paulo Gallo and et al.}, year={2020}, month={Jan}, pages={5–12} }
 @article{ribeiro_ayllon_malirat_portela camara_giordano dias_louzada_fernandes-ferreira_medronho_acevedo_2019, title={High Prevalence of a Newly Discovered Wutai Mosquito Phasivirus in Mosquitoes from Rio de Janeiro, Brazil}, volume={10}, ISSN={["2075-4450"]}, DOI={10.3390/insects10050135}, abstractNote={Many RNA viruses have recently emerged, threatening humans and causing harm to animals and plants. Bunyaviruses represent one of the largest groups of RNA viruses and are able to infect a wide range of hosts (invertebrates, vertebrates, and plants). Recently, new insect-specific viruses have been isolated from mosquitoes and phlebotomine sandflies worldwide. Little is known regarding the impact of these viruses on the vector life cycles and the stages of oviposition, breeding, blood feeding, and the mosquito’s lifespan. This study describes, for the first time in South America, the detection and characterization of a recently discovered bunyavirus corresponding to the Wutai mosquito phasivirus, confirming its high prevalence in the Culex spp. and Aedes spp. mosquitoes collected in the urban environment of Rio de Janeiro city, Brazil. The knowledge of the mosquito’s insect-specific virus infection can improve virus evolution studies and may contribute to the understanding of intrinsic factors that influence vector competence to transmit pathogenic viruses.}, number={5}, journal={INSECTS}, author={Ribeiro, Mario Sergio and Ayllon, Tania and Malirat, Viviana and Portela Camara, Daniel Cardoso and Giordano Dias, Cristina Maria and Louzada, Guilherme and Fernandes-Ferreira, Davis and Medronho, Roberto de Andrade and Acevedo, Renata Campos}, year={2019}, month={May} }
 @article{cirne-santos_barros_richter nogueira_azevedo_yamamoto_silva meira_vasconcelos_ratcliffe_teixeira_schmidt-chanasit_et al._2019, title={Inhibition by Marine Algae of Chikungunya Virus Isolated From Patients in a Recent Disease Outbreak in Rio de Janeiro}, volume={10}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2019.02426}, abstractNote={Chikungunya virus (CHIKV) infection is one of the most challenging re-emergent diseases caused by a virus, and with no specific antiviral treatment it has now become a major public health concern. In this investigation, 25 blood samples were collected from patients with characteristic CHIKV symptoms and submitted to a virus isolation protocol, which detected 3 CHIKV isolates. These samples were evaluated by sequencing for the characterization of the strains and any homology to viruses circulating in Brazil during a recent outbreak. These viruses were used for the development of antiviral assays. Subsequently, the inhibitory effects of seaweed extracts on CHIKV replication were studied. The marine species of algae tested were Bryothamnion triquetrum, Caulerpa racemosa, Laurencia dendroidea, Osmundaria obtusiloba, Ulva fasciata, and Kappaphycus alvarezii, all of which are found in different countries including Brazil. The results revealed high levels of CHIKV inhibition, including extracts of O. obtusiloba with inhibition values of 1.25 μg/mL and a selectivity index of 420. Viral inhibition was dependent on the time of addition of extract of O. obtusiloba to the infected cells, with the optimal inhibition occurring up to 16 h after infection. Neuron evaluations with O. obtusiloba were performed and demonstrated low toxicity, and in infected neurons we observed high inhibitory activity in a dose-dependent manner. These results indicate that the algal extracts may be promising novel candidates for the development of therapeutic agents against CHIKV infections.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Cirne-Santos, Claudio Cesar and Barros, Caroline de Souza and Richter Nogueira, Caio Cesar and Azevedo, Renata Campos and Yamamoto, Kristie Aimi and Silva Meira, Guilherme Louzada and Vasconcelos, Zilton Farias and Ratcliffe, Norman Arthur and Teixeira, Valeria Laneuville and Schmidt-Chanasit, Jonas and et al.}, year={2019}, month={Oct} }
 @article{gonzaga_gomes_marra_silva_gomes_ferreira_santos_pinto_ratcliffe_cirne-santos_et al._2019, title={Inhibition of Zika Virus Replication by Synthetic Bis-Naphthoquinones}, volume={30}, ISSN={["1678-4790"]}, DOI={10.21577/0103-5053.20190071}, abstractNote={Zika virus (ZIKV) is a mosquito-borne pathogen which is a current global public health concern. There are currently no approved vaccines or antivirals against ZIKV infection. Taking into account that naphthoquinones have shown promising antiviral activity, the aim of this study was to describe the screening of two bis-naphthoquinones series against ZIKV. Twenty seven compounds were evaluated against ZIKV using Vero cells. The findings showed that among the compounds analyzed four were promising. Compound 3,3’-((2-nitrophenyl)methylene)bis(2-hydroxynaphthalene1,4-dione) containing the nitro group at the ortho position showed the best selectivity index, followed by compound 3,3’-(4-chlorophenylmethylene)bis(naphthalene-1,2,4-triyl triacetate) with the chlorophenylmethylene radical. These results demonstrate that these bis-naphthoquinones are largely effective in inhibiting the replication of ZIKV.}, number={8}, journal={JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY}, author={Gonzaga, Daniel T. G. and Gomes, Rafaela S. P. and Marra, Roberta K. F. and Silva, Fernando C. and Gomes, Max W. L. and Ferreira, Davis E. and Santos, Raissa M. A. and Pinto, Ana M. and Ratcliffe, Norman Arthur and Cirne-Santos, Claudio C. and et al.}, year={2019}, month={Aug}, pages={1697–1706} }
 @article{hernandez_glaros_rizzo_ferreira_2019, title={Purification and Proteomic Analysis of Alphavirus Particles from Sindbis Virus Grown in Mammalian and Insect Cells}, volume={9}, ISSN={["2331-8325"]}, DOI={10.21769/BioProtoc.3239}, abstractNote={Current mass spectrometry (MS) methods and new instrumentation now allow for more accurate identification of proteins in low abundance than previous protein fractionation and identification methods. It was of interest if this method could serve to define the virus proteome of a membrane-containing virus. To evaluate the efficacy of mass spec to determine the proteome of medically important viruses, Sindbis virus (SINV), the prototypical alphavirus was chosen for evaluation. This model system was chosen specifically because the alphaviruses contain members which are human pathogens, this virus is well defined biochemically and structurally, and grows to high titers in both vertebrate and non-vertebrate host cells. The SINV proteome was investigated using this method to determine if host proteins are specifically packaged into infectious virions. It was also of interest if the SINV proteome, when grown in multiple host cells representing vertebrate and mosquito hosts, incorporated specific host proteins from all hosts. Observation of recurrent or distinctive proteins in the virus proteome aided in the determination of proteins incorporated into the virion as opposed to those bound to the particle exterior. Mass spectrometry analysis identified the total protein content of purified virions within limits of detection. The most significant finding was that in addition to the host proteins, SINV non-structural protein 2 (nsP2) was detected within virions grown in all host cells examined. This analysis identified host factors not previously associated with alphavirus entry, replication, or egress, identifying at least one host factor integrally involved in alphavirus replication. Key to the success of this analysis is the method of virus purification which must deliver measurably infectious virus free of high levels of contaminants. For SINV and other members of the alphavirus family, this is accomplished by isopycnic centrifugation through potassium tartrate, followed by a high salt wash.}, number={10}, journal={BIO-PROTOCOL}, author={Hernandez, Raquel and Glaros, Trevor and Rizzo, Gabrielle and Ferreira, Davis F.}, year={2019}, month={May} }
 @misc{salles_sa-guimaraes_alvarenga_guimaraes-ribeiro_meneses_castro-salles_santos_amaral melo_soares_ferreira_et al._2018, title={History, epidemiology and diagnostics of dengue in the American and Brazilian contexts: a review}, volume={11}, ISSN={["1756-3305"]}, DOI={10.1186/s13071-018-2830-8}, abstractNote={Dengue virus (DENV), an arbovirus transmitted by mosquitoes, has become a major threat to American human life, reaching approximately 23 million cases from 1980 to 2017. Brazil is among the countries most affected by this terrible viral disease, with 13.6 million cases. DENV has four different serotypes, DENV1-4, which show a broad clinical spectrum. Dengue creates a staggering epidemiological and economic burden for endemic countries. Without a specific therapy and with a commercial vaccine that presents some problems relative to its full effectiveness, initiatives to improve vector control strategies, early disease diagnostics and the development of vaccines and antiviral drugs are priorities. In this study, we present the probable origins of dengue in America and the trajectories of its spread. Overall, dengue diagnostics are costly, making the monitoring of dengue epidemiology more difficult and affecting physicians' therapeutic decisions regarding dengue patients, especially in developing countries. This review also highlights some recent and important findings regarding dengue in Brazil and the Americas. We also summarize the existing DENV polymerase chain reaction (PCR) diagnostic tests to provide an improved reference since these tests are useful and accurate at discriminating DENV from other flaviviruses that co-circulate in the Americas. Additionally, these DENV PCR assays ensure virus serotyping, enabling epidemiologic monitoring.}, journal={PARASITES & VECTORS}, author={Salles, Tiago Souza and Sa-Guimaraes, Thayane da Encarnacao and Alvarenga, Evelyn Seam and Guimaraes-Ribeiro, Victor and Meneses, Marcelo Damiao and Castro-Salles, Patricia Faria and Santos, Carlucio Rocha and Amaral Melo, Ana Claudia and Soares, Marcia Regina and Ferreira, Davis Fernandes and et al.}, year={2018}, month={Apr} }
 @article{caldas_ferreira_pereira freitas_2018, title={Prostaglandin A(1) triggers Mayaro virus inhibition and heat shock protein 70 expression in an epithelial cell model}, volume={51}, ISSN={["0037-8682"]}, DOI={10.1590/0037-8682-0235-2018}, abstractNote={INTRODUCTION
The Mayaro virus (MAYV), which is an arbovirus closely related to the Chikungunya virus, causes a dengue-like acute illness that is endemic to Central and South America. We investigated the anti-MAYV activity of prostaglandin A1 (PGA1), a hormone which exhibits antiviral activity against both ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) viruses. Further, we examined the effects of inducting the stress protein HSP70 following PGA1 treatment.


METHODS
Hep-2 cells infected with MAYV were treated with PGA1 (0.1-6μg/ml) 12h before infection and for different periods post-infection. Inhibition of viral replication inhibition was analyzed via viral titer determination, whereas the effect of PGA1 on viral morphogenesis was examined via transmission electron microscopy (TEM). Autoradiography (with 35S methionine labeling) and western blotting were used to assess the effect of PGA1 treatment on viral and cellular protein synthesis, and on HSP70 induction, respectively.


RESULTS
PGA1 strongly reduced viral replication in Hep-2 cells, particularly when added during the early stages of viral replication. Although PGA1 treatment inhibited viral replication by 95% at 24 hours post-infection (hpi), viral structural protein synthesis was inhibited only by 15%. TEM analysis suggested that PGA1 inhibited replication before viral morphogenesis. Western blot and densitometry analyses showed that PGA1 treatment increased HSP70 protein levels, although this was not detectable via autoradiography.


CONCLUSIONS
PGA1 inhibits MAYV replication in Hep-2 cells at early stages of viral replication, prior to production of viral structural proteins, possibly via HSP70 induction.}, number={5}, journal={REVISTA DA SOCIEDADE BRASILEIRA DE MEDICINA TROPICAL}, author={Caldas, Lucio Ayres and Ferreira, Davis Fernandes and Pereira Freitas, Tania Rosaria}, year={2018}, pages={584–590} }
 @article{vancini_wang_ferreira_hernandez_brown_2013, title={Alphavirus Genome Delivery Occurs Directly at the Plasma Membrane in a Time- and Temperature-Dependent Process}, volume={87}, ISSN={["0022-538X"]}, DOI={10.1128/jvi.03412-12}, abstractNote={ABSTRACT It is widely held that arboviruses such as the alphavirus Sindbis virus gain entry into cells by a process of receptor-mediated endocytosis followed by membrane fusion in the acid environment of the endosome. We have used an approach of direct observation of Sindbis virus entry into cells by electron microscopy and immunolabeling of virus proteins with antibodies conjugated to gold beads. We found that upon attaching to the cell surface, intact RNA-containing viruses became empty shells that could be identified only by antibody labeling. We found that the rate at which full particles were converted to empty particles increased with time and temperature. We found that this entry event takes place at temperatures that inhibit both endosome formation and membrane fusion. We conclude that entry of alphaviruses is by direct penetration of cell plasma membranes through a pore structure formed by virus and, possibly, host proteins.}, number={8}, journal={JOURNAL OF VIROLOGY}, author={Vancini, Ricardo and Wang, Gongbo and Ferreira, Davis and Hernandez, Raquel and Brown, Dennis T.}, year={2013}, month={Apr}, pages={4352–4359} }
 @article{west_hernandez_ferreira_brown_2006, title={Mutations in the endodomain of Sindbis virus glycoprotein E2 define sequences critical for virus assembly}, volume={80}, ISSN={["1098-5514"]}, DOI={10.1128/jvi.80.9.4458-4468.2006}, abstractNote={ABSTRACT Envelopment of Sindbis virus at the plasma membrane is a multistep process in which an initial step is the association of the E2 protein via a cytoplasmic endodomain with the preassembled nucleocapsid. Sindbis virus is vectored in nature by blood-sucking insects and grows efficiently in a number of avian and mammalian vertebrate hosts. The assembly of Sindbis virus, therefore, must occur in two very different host cell environments. Mammalian cells contain cholesterol which insect membranes lack. This difference in membrane composition may be critical in determining what requirements are placed on the E2 tail for virus assembly. To examine the interaction between the E2 tail and the nucleocapsid in Sindbis virus, we have produced substitutions and deletions in a region of the E2 tail (E2 amino acids 408 to 415) that is initially integrated into the endoplasmic reticulum. This sequence was identified as being critical for nucleocapsid binding in an in vitro peptide protection assay. The effects of these mutations on virus assembly and function were determined in both vertebrate and invertebrate cells. Amino acid substitutions (at positions E2: 408, 410, 411, and 413) reduced infectious virus production in a position-dependent fashion but were not efficient in disrupting assembly in mammalian cells. Deletions in the E2 endodomain (Δ406-407, Δ409-411, and Δ414-417) resulted in the failure to assemble virions in mammalian cells. Electron microscopy of BHK cells transfected with these mutants revealed assembly of nucleocapsids that failed to attach to membranes. However, introduction of these deletion mutants into insect cells resulted in the assembly of virus-like particles but no assayable infectivity. These data help define protein interactions critical for virus assembly and suggest a fundamental difference between Sindbis virus assembly in mammalian and insect cells.}, number={9}, journal={JOURNAL OF VIROLOGY}, author={West, J and Hernandez, R and Ferreira, D and Brown, DT}, year={2006}, month={May}, pages={4458–4468} }
 @article{mudiganti_hernandez_ferreira_brown_2006, title={Sindbis virus infection of two model insect cell systems - A comparative study}, volume={122}, DOI={10.1016/j.virusres.2006.06.007}, abstractNote={Sindbis, the prototype of the Alphaviruses causes mosquito-borne diseases in mammals and replicates in a wide variety of vertebrate and invertebrate cell cultures. This characteristic can be exploited to use the vast array of Drosophila genetic information available for investigations of the interaction of Sindbis virus with an alternate invertebrate host. For this purpose, a comparative study of Sindbis virus infection of Schnieder-2 Drosophila (S2) cells to cells of the mosquito Aedes albopictus (clone U4.4) was undertaken. After infection, vertebrate cells die within 24–48 h, while invertebrate cell cultures survive an acute phase of infection and become persistently infected. In this study, infection of a model Drosophila system, S2 cells, was compared to U4.4 cells. Virus production, the time course of the establishment of persistence and changes in growth properties of the S2 cells upon infection, were studied in comparison to those of the U4.4 cells. S2 cells survived acute Sindbis infection without any significant cytopathology and continued to produce low levels of virus characteristic of persistently infected cells. S2 cells produced 10 PFU/cell on day 1 post-infection, which falls to 2 PFU/cell on day 2. This result is in contrast to U4.4 cells, which produce peak virus titer on day 2 post-infection and establish persistence by day 5. Onset of the persistent phase of infection of either U4.4 or S2 cells did not result in any change in morphology or growth characteristics. This study establishes S2 cells as an additional invertebrate model system to study the interactions of an invertebrate host with Sindbis virus.}, number={1-2}, journal={Virus Research}, author={Mudiganti, U. and Hernandez, R. and Ferreira, D. and Brown, D. T.}, year={2006}, pages={28–34} }
 @article{hernandez_ferreira_sinodis_litton_brown_2005, title={Single amino acid insertions at the junction of the Sindbis virus e2 transmembrane domain and endodomain disrupt virus envelopment and alter infectivity}, volume={79}, DOI={10.1128/JVI.79.7682-7697.2005}, number={12}, journal={Journal of Virology}, author={Hernandez, R. and Ferreira, D. and Sinodis, C. and Litton, K. and Brown, D. T.}, year={2005}, pages={7682–7697} }
 @article{paredes_ferreira_horton_saad_tsuruta_johnston_klimstra_ryman_hernandez_chiu_et al._2004, title={Conformational changes in Sindbis virions resulting from exposure to low pH and interactions with cells suggest that cell penetration may occur at the cell surface in the absence of membrane fusion}, volume={324}, DOI={10.1016/j.virus.2004.03.046}, number={2}, journal={Virology}, author={Paredes, A. M. and Ferreira, D. and Horton, M. and Saad, A. and Tsuruta, H. and Johnston, R. and Klimstra, W. and Ryman, K. and Hernandez, R. and Chiu, W. and et al.}, year={2004}, pages={373–386} }
 @article{hernandez_sinodis_horton_ferreira_yang_brown_2003, title={Deletions in the transmembrane domain of a Sindbis virus glycoprotein alter virus infectivity, stability, and host range}, volume={77}, ISSN={["0022-538X"]}, DOI={10.1128/JVI.77.23.12710-12719.2003}, abstractNote={ABSTRACT The alphaviruses are composed of two icosahedral protein shells, one nested within the other. A membrane bilayer derived from the host cell is sandwiched between the protein shells. The protein shells are attached to one another by protein domains which extend one of the proteins of the outer shell through the membrane bilayer to attach to the inner shell. We have examined the interaction of the membrane-spanning domain of one of the membrane glycoproteins with the membrane bilayer and with other virus proteins in an attempt to understand the role this domain plays in virus assembly and function. Through incremental deletions, we have reduced the length of a virus membrane protein transmembrane domain from its normal 26 amino acids to 8 amino acids. We examined the effect of these deletions on the assembly and function of virus particles. We found that progressive truncations in the transmembrane domain profoundly affected production of infectious virus in a cyclic fashion. We also found that membrane composition effects protein-protein and protein-membrane interactions during virus assembly.}, number={23}, journal={JOURNAL OF VIROLOGY}, author={Hernandez, R and Sinodis, C and Horton, M and Ferreira, D and Yang, CN and Brown, DT}, year={2003}, month={Dec}, pages={12710–12719} }