RESUMO
Bifunctional catalysis in zeolites possessing both Brønsted and Lewis acid sites offers unique opportunities to tailor shape selectivity and enhance catalyst performance. Here, we examine the impact of framework and extra-framework gallium species on enriched aromatics production in zeolite ZSM-5. We compare three distinct methods of preparing Ga-ZSM-5 and reveal direct (single step) synthesis leads to optimal catalysts compared to post-synthesis methods. Using a combination of state-of-the-art characterization, catalyst testing, and density functional theory calculations, we show that Ga Lewis acid sites strongly favor aromatization. Our findings also suggest Ga(framework)-Ga(extra-framework) pairings, which can only be achieved in materials prepared by direct synthesis, are the most energetically favorable sites for reaction pathways leading to aromatics. Calculated acid site exchange energies between extra-framework Ga at framework sites comprised of either Al or Ga reveal a site-specific preference for stabilizing Lewis acids, which is qualitatively consistent with experimental measurements. These findings indicate the possibility of tailoring Lewis acid siting by the placement of Ga heteroatoms at distinct tetrahedral sites in the zeolite framework, which can have a marked impact on catalyst performance relative to conventional H-ZSM-5.
RESUMO
BACKGROUND: The rapid and reliable detection of infectious agents is one of the most challenging tasks in scenarios lacking well-equipped laboratory infrastructure, like diagnostics in rural areas of developing countries. Commercially available point-of-care diagnostic tests for emerging and rare diseases are particularly scarce. RESULTS: In this work we present a point-of-care test for the detection of Orthopoxviruses (OPV). The OPV ABICAP assay detects down to 1 × 104 plaque forming units/mL of OPV particles within 45 min. It can be applied to clinical material like skin crusts and detects all zoonotic OPV infecting humans, including Vaccinia, Cowpox, Monkeypox, and most importantly Variola virus. CONCLUSIONS: Given the high sensitivity and the ease of handling, the novel assay could be highly useful for on-site diagnostics of suspected Monkeypox virus infections in areas lacking proper laboratory infrastructure as well as rapid on-site testing of suspected bioterrorism samples.
Assuntos
Filtração/métodos , Imunoensaio/métodos , Orthopoxvirus/isolamento & purificação , Sistemas Automatizados de Assistência Junto ao Leito , Infecções por Poxviridae/diagnóstico , Infecções por Poxviridae/veterinária , Virologia/métodos , Animais , Humanos , Sensibilidade e Especificidade , Fatores de TempoRESUMO
Brincidofovir (CMX001), a lipid conjugate of the acyclic nucleotide phosphonate cidofovir, is under development for smallpox treatment using "the Animal Rule," established by the FDA in 2002. Brincidofovir reduces mortality caused by orthopoxvirus infection in animal models. Compared to cidofovir, brincidofovir has increased potency, is administered orally, and shows no evidence of nephrotoxicity. Here we report that the brincidofovir half-maximal effective concentration (EC50) against five variola virus strains in vitro averaged 0.11 µM and that brincidofovir was therefore nearly 100-fold more potent than cidofovir.
Assuntos
Antivirais/farmacologia , Citosina/análogos & derivados , Organofosfonatos/farmacologia , Varíola/tratamento farmacológico , Vírus da Varíola/efeitos dos fármacos , Animais , Linhagem Celular , Chlorocebus aethiops , Cidofovir , Citosina/farmacologia , DNA Viral/análise , DNA Viral/genética , Modelos Animais de Doenças , Humanos , Técnicas In Vitro , Testes de Sensibilidade Microbiana , Vírus da Varíola/crescimento & desenvolvimentoRESUMO
The Candida albicans fitness test is a whole cell screening platform that utilizes a mixed-pool of C. albicans mutants, each of which carries a heterozygous deletion of a particular gene. In the presence of an antifungal inhibitor, a subset of these mutants exhibits a growth phenotype of hypersensitivity or hyposensitivity. Collectively these mutants reflect aspects of the mechanism of action of the compound in question. In the course of screening natural products a culture of Streptomyces sp. MS-1-4 was discovered to produce a compound, dretamycin, which yielded a fitness profile exhibiting significant hypersensitivity of the DRE2 heterozygote and hyposensitivity of the DIP5 heterozygote. Herein we report the production, isolation, and structure elucidation of dretamycin.
Assuntos
Antifúngicos/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Proteínas Fúngicas/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Pirróis/isolamento & purificação , Streptomyces/química , Antifúngicos/química , Antifúngicos/farmacologia , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Candida albicans/efeitos dos fármacos , Proteínas Fúngicas/genética , Proteínas Ferro-Enxofre/genética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Pirróis/química , Pirróis/farmacologiaRESUMO
Identification of human monkeypox cases during 2005 in southern Sudan (now South Sudan) raised several questions about the natural history of monkeypox virus (MPXV) in Africa. The outbreak area, characterized by seasonally dry riverine grasslands, is not identified as environmentally suitable for MPXV transmission. We examined possible origins of this outbreak by performing phylogenetic analysis of genome sequences of MPXV isolates from the outbreak in Sudan and from differing localities. We also compared the environmental suitability of study localities for monkeypox transmission. Phylogenetically, the viruses isolated from Sudan outbreak specimens belong to a clade identified in the Congo Basin. This finding, added to the political instability of the area during the time of the outbreak, supports the hypothesis of importation by infected animals or humans entering Sudan from the Congo Basin, and person-to-person transmission of virus, rather than transmission of indigenous virus from infected animals to humans.
Assuntos
Surtos de Doenças , Mpox/virologia , Animais , Genes Virais , Humanos , Tipagem Molecular , Mpox/epidemiologia , Mpox/transmissão , Monkeypox virus/classificação , Monkeypox virus/genética , Monkeypox virus/isolamento & purificação , Filogenia , Filogeografia , Análise de Sequência de DNA , Sudão/epidemiologiaRESUMO
BACKGROUND: Cowpox virus is an Orthopoxvirus that can cause infections in humans and a variety of animals. Infections occur in Eurasia; infections in humans and animals have not been reported in the United States. This report describes the occurrence of the first known human case of laboratory-acquired cowpox virus infection in the United States and the ensuing investigation. METHODS: The patient and laboratory personnel were interviewed, and laboratory activities were reviewed. Real-time polymerase chain reaction (PCR) and serologic assays were used to test the patient's specimens. PCR assays were used to test specimens obtained during the investigation. RESULTS: A specimen from the patient's lesion tested positive for cowpox virus DNA. Genome sequencing revealed a recombinant region consistent with a strain of cowpox virus stored in the research laboratory's freezer. Cowpox virus contamination was detected in 6 additional laboratory stocks of viruses. Orthopoxvirus DNA was present in 3 of 20 environmental swabs taken from laboratory surfaces. CONCLUSIONS: The handling of contaminated reagents or contact with contaminated surfaces was likely the mode of transmission. Delays in recognition and diagnosis of this infection in a laboratory researcher underscore the importance of a thorough patient history-including occupational information-and laboratory testing in facilitating a prompt investigation and application of control and remediation measures.
Assuntos
Vírus da Varíola Bovina/isolamento & purificação , Varíola Bovina/virologia , DNA Viral/isolamento & purificação , Transmissão de Doença Infecciosa do Paciente para o Profissional , Infecção Laboratorial/virologia , Pessoal de Laboratório , Varíola Bovina/epidemiologia , Varíola Bovina/transmissão , Vírus da Varíola Bovina/genética , Contaminação por DNA , DNA Viral/genética , Humanos , Infecção Laboratorial/epidemiologia , Infecção Laboratorial/transmissão , Estados Unidos/epidemiologiaRESUMO
Progressive vaccinia (PV) is a rare but potentially lethal complication that develops in smallpox vaccine recipients with severely impaired cellular immunity. We describe a patient with PV who required treatment with vaccinia immune globulin and who received 2 investigational agents, ST-246 and CMX001. We describe the various molecular, pharmacokinetic, and immunologic studies that provided guidance to escalate and then successfully discontinue therapy. Despite development of resistance to ST-246 during treatment, the patient had resolution of PV. This case demonstrates the need for continued development of novel anti-orthopoxvirus pharmaceuticals and the importance of both intensive and timely clinical and laboratory support in management of PV.
Assuntos
Anticorpos Antivirais/administração & dosagem , Antivirais/administração & dosagem , Benzamidas/administração & dosagem , Citosina/análogos & derivados , Isoindóis/administração & dosagem , Organofosfonatos/administração & dosagem , Vaccinia virus/isolamento & purificação , Vacínia/diagnóstico , Vacínia/tratamento farmacológico , Adulto , Antivirais/farmacologia , Citosina/administração & dosagem , Farmacorresistência Viral , Humanos , Imunoglobulinas/administração & dosagem , Masculino , Vacina Antivariólica/administração & dosagem , Vacina Antivariólica/efeitos adversos , Resultado do TratamentoRESUMO
Vaccinia virus (VacV) enters mammalian cells, replicates extranuclearly, and produces virions that move to the cell surface along microtubules, fuse with the plasma membrane, and move from infected cells toward apposing cells on actin-filled membranous protrusions or actin tails. To form actin tails, cell-associated enveloped virions (CEV) require Abl and Src family tyrosine kinases. Furthermore, release of CEV from the cell requires Abl but not Src family tyrosine kinases and is blocked by imatinib mesylate (STI-571; Gleevec), an Abl family kinase inhibitor used to treat chronic myelogenous leukemia in humans. Here we demonstrate that the Poxviridae family members monkeypox virus (MPX) and variola virus (VarV) use conserved mechanisms for actin motility and extracellular enveloped virion (EEV) release. Furthermore, we show that imatinib mesylate is effective in a mouse model of infection with VacV, whether delivered prophylactically or postinfection, and restricts spread of virions from the site of inoculation. While inhibitors of both Src and Abl family kinases, such as dasatinib (BMS-354825; Sprycel), are effective in limiting dissemination of VacV, VarV, and MPX in vitro, members of this class of drugs appear to have immunosuppressive effects in vivo that preclude their use as anti-infectives. Together, these data suggest a possible utility for imatinib mesylate in treating smallpox or MPX infections or complications associated with vaccination.
Assuntos
Monkeypox virus/enzimologia , Proteínas Proto-Oncogênicas c-abl/metabolismo , Vírus da Varíola/enzimologia , Vírion/fisiologia , Liberação de Vírus/fisiologia , Quinases da Família src/metabolismo , Células 3T3 , Actinas/metabolismo , Animais , Benzamidas , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Feminino , Humanos , Mesilato de Imatinib , Camundongos , Camundongos Endogâmicos BALB C , Monkeypox virus/efeitos dos fármacos , Monkeypox virus/fisiologia , Piperazinas/farmacologia , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Vacínia/tratamento farmacológico , Vacínia/prevenção & controle , Vacínia/virologia , Vaccinia virus/efeitos dos fármacos , Vaccinia virus/enzimologia , Vírus da Varíola/efeitos dos fármacos , Vírus da Varíola/fisiologia , Liberação de Vírus/efeitos dos fármacos , Quinases da Família src/antagonistas & inibidoresRESUMO
Smallpox preparedness research has led to development of antiviral therapies for treatment of serious orthopoxvirus infections. Monkeypox virus is an emerging, zoonotic orthopoxvirus which can cause severe and transmissible disease in humans, generating concerns for public health. Monkeypox virus infection results in a systemic, febrile-rash illness closely resembling smallpox. Currently, there are no small-molecule antiviral therapeutics approved to treat orthopoxvirus infections of humans. The prairie dog, using monkeypox virus as a challenge virus, has provided a valuable nonhuman animal model in which monkeypox virus infection closely resembles human systemic orthopoxvirus illness. Here, we assess the efficacy of the antiorthopoxvirus compound ST-246 in prairie dogs against a monkeypox virus challenge of 65 times the 50% lethal dose (LD(50)). Animals were infected intranasally and administered ST-246 for 14 days, beginning on days 0, 3, or after rash onset. Swab and blood samples were collected every 2 days and analyzed for presence of viral DNA by real-time PCR and for viable virus by tissue culture. Seventy-five percent of infected animals that received vehicle alone succumbed to infection. One hundred percent of animals that received ST-246 survived challenge, and animals that received treatment before symptom onset remained largely asymptomatic. Viable virus and viral DNA were undetected or at greatly reduced levels in animals that began treatment on 0 or 3 days postinfection, compared to control animals or animals treated post-rash onset. Animals treated after rash onset manifested illness, but all recovered. Our results indicate that ST-246 can be used therapeutically, following onset of rash illness, to treat systemic orthopoxvirus infections.
Assuntos
Antivirais/administração & dosagem , Benzamidas/administração & dosagem , Isoindóis/administração & dosagem , Monkeypox virus/patogenicidade , Infecções por Poxviridae/tratamento farmacológico , Canal Anal/virologia , Animais , Sangue/virologia , DNA Viral/genética , DNA Viral/isolamento & purificação , Modelos Animais de Doenças , Olho/virologia , Humanos , Orofaringe/virologia , Infecções por Poxviridae/mortalidade , Infecções por Poxviridae/patologia , Sciuridae , Análise de Sobrevida , Resultado do Tratamento , Carga ViralRESUMO
Emergence of bacterial resistance has eroded the effectiveness of many life saving antibiotics leading to an urgent need for new chemical classes of antibacterial agents. We have applied a Staphylococcus aureus fitness test strategy to natural products screening to meet this challenge. In this paper we report the discovery of kibdelomycin A, a demethylated congener of kibdelomycin, the representative of a novel class of antibiotics produced by a new strain of Kibdelosporangium. Kibdelomycin A is a potent inhibitor of DNA gyrase and topoisomerase IV, inhibits DNA synthesis and shows whole cell antibiotic activity, albeit, less potently than kibdelomycin. Kibdelomycin C-33 acetate and tetrahydro-bisdechloro derivatives of kibdelomycin were prepared which helped define a basic SAR of the family.
Assuntos
Aminoglicosídeos/isolamento & purificação , Aminoglicosídeos/farmacologia , Antibacterianos/química , Naftalenos/isolamento & purificação , Naftalenos/farmacologia , Actinomycetales/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , DNA Girase/metabolismo , DNA Topoisomerase IV/antagonistas & inibidores , DNA Topoisomerase IV/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Inibidores Enzimáticos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Conformação Molecular , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Relação Estrutura-Atividade , Inibidores da Topoisomerase IIRESUMO
Vaccinia virus is an orthopoxvirus used in the live vaccine against smallpox. Vaccinia virus infections can be transmissible and can cause severe complications in those with weakened immune systems. We report on a cluster of 4 cases of vaccinia virus infection in Maryland, USA, likely acquired at a martial arts gym.
Assuntos
Vaccinia virus/fisiologia , Vacínia/transmissão , Adulto , Sequência de Bases , DNA Viral/genética , Hemaglutinação por Vírus/genética , Humanos , Imunoglobulina M/sangue , Masculino , Maryland , Dados de Sequência Molecular , Alinhamento de Sequência , Análise de Sequência de DNA , Pele/patologia , Vacina Antivariólica/efeitos adversos , Vacina Antivariólica/normas , Vacínia/imunologia , Vacínia/virologia , Vaccinia virus/genética , Vaccinia virus/imunologiaRESUMO
During a suspected monkeypox outbreak in the Republic of Congo, we documented transmission of varicella-zoster virus (VZV) infection with palm and sole manifestations among 5 family members. Genotyping results confirmed the VZV strain European E2, a genotype not previously reported in Africa. VZV with palm and sole involvement should be considered when differentiating a monkeypox diagnosis.
Assuntos
Mãos/patologia , Herpes Zoster/fisiopatologia , Herpes Zoster/transmissão , Perna (Membro)/patologia , Adolescente , Adulto , Criança , Congo/epidemiologia , DNA Viral/genética , Diagnóstico Diferencial , Saúde da Família , Feminino , Genótipo , Herpes Zoster/diagnóstico , Herpes Zoster/epidemiologia , Herpesvirus Humano 3/classificação , Herpesvirus Humano 3/genética , Herpesvirus Humano 3/isolamento & purificação , Humanos , Lactente , Masculino , Mpox/diagnóstico , FilogeniaRESUMO
Since the eradication of smallpox and the cessation of routine childhood vaccination for smallpox, the proportion of the world's population susceptible to infection with orthopoxviruses, such as variola virus (the causative agent of smallpox) and monkeypox virus, has grown substantially. In the United States, the only vaccines for smallpox licensed by the Food and Drug Administration (FDA) have been live virus vaccines. Unfortunately, a substantial number of people cannot receive live virus vaccines due to contraindications. Furthermore, no antiviral drugs have been fully approved by the FDA for the prevention or treatment of orthopoxvirus infection. Here, we show the inhibitory effect of one new antiviral compound, ST-246, on the in vitro growth properties of six variola virus strains and seven monkeypox virus strains. We performed multiple assays to monitor the cytopathic effect and to evaluate the reduction of viral progeny production and release in the presence of the compound. ST-246 had 50% effective concentrations of Assuntos
Benzamidas/farmacologia
, Isoindóis/farmacologia
, Mpox/tratamento farmacológico
, Vírus da Varíola/efeitos dos fármacos
, Vírus da Varíola/crescimento & desenvolvimento
, Animais
, Chlorocebus aethiops
, Ensaio Cometa
, Efeito Citopatogênico Viral/efeitos dos fármacos
, Relação Dose-Resposta a Droga
, Imuno-Histoquímica
, Concentração Inibidora 50
, Mpox/genética
, Mpox/virologia
, Vírus da Varíola/genética
, Ensaio de Placa Viral
RESUMO
Antisense-based screening strategies can be used to sensitize a microorganism and selectively detect inhibitors against a particular cellular target of interest. A strain of Staphylococcus aureus that generates an antisense RNA against SecA,a central member of the protein secretion machinery, has been used to screen for novel antibacterials. Possible inhibitors of the SecA ATP-ase were selected with a high-throughput, two-plate agar-based whole cell differential sensitivity screen. After screening a library of over 115 000 natural products extracts with the SecA antisense strain, an extract of Geomyces pannorum was identified as providing increased activity against the sensitized strain as compared with the wild-type control. Bioassay-guided isolation of the active component from this fungal extract provided a new cis-decalin secondary metabolite, which we have named pannomycin.
Assuntos
Antibacterianos/isolamento & purificação , Ascomicetos/química , Naftalenos/isolamento & purificação , RNA Antissenso/genética , Adenosina Trifosfatases/antagonistas & inibidores , Antibacterianos/química , Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Membrana Transportadoras , Testes de Sensibilidade Microbiana , Estrutura Molecular , Naftalenos/química , Naftalenos/farmacologia , RNA Antissenso/metabolismo , Canais de Translocação SEC , Proteínas SecA , Staphylococcus aureus/efeitos dos fármacos , EstereoisomerismoRESUMO
The Candida albicans Fitness Test, a whole-cell screening platform, was used to profile crude fermentation extracts for novel antifungal natural products with interesting mechanisms of action. An extract with intrinsic antifungal activity from the fungus Fusarium larvarum displayed a Fitness Test profile that strongly implicated mRNA processing as the molecular target responsible for inhibition of fungal growth. Isolation of the active components from this sample identified a novel class of isoxazolidinone-containing natural products, which we have named parnafungins. These natural products were isolated as an interconverting mixture of four structural- and stereoisomers. The isomerization of the parnafungins was due to a retro-Michael ring-opening and subsequent reformation of a xanthone ring system. This interconversion was blocked by methylation of an enol moiety. Structure elucidation of purified parnafungin derivatives was accomplished by X-ray crystallography and NMR analysis. The biochemical target of these natural products has been identified as the fungal polyadenosine polymerase. Parnafungins demonstrated broad spectrum antifungal activity with no observed activity against gram-positive or gram-negative bacteria. The intact isoxazolidinone ring was required for antifungal activity. In addition, the natural products were efficacious in a mouse model of disseminated candidiasis.
Assuntos
Antifúngicos/isolamento & purificação , Fusarium/química , Oxazolidinonas/isolamento & purificação , Antifúngicos/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Cristalografia por Raios X , Testes de Sensibilidade Microbiana , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , Oxazolidinonas/química , Oxazolidinonas/farmacologia , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria Infravermelho , Espectrofotometria UltravioletaRESUMO
CDC designated category A infectious agents pose a major risk to national security and require special action for public health preparedness. They include viruses that cause viral hemorrhagic fever (VHF) syndrome as well as variola virus, the agent of smallpox. VHF is characterized by hemorrhage and fever with multi-organ failure leading to high morbidity and mortality. Smallpox, a prior scourge, has been eradicated for decades, making it a particularly serious threat if released nefariously in the essentially non-immune world population. Early detection of the causative agents, and the ability to distinguish them from other pathogens, is essential to contain outbreaks, implement proper control measures, and prevent morbidity and mortality. We have developed a multiplex detection assay that uses several species-specific PCR primers to generate amplicons from multiple pathogens; these are then targeted in a ligase detection reaction (LDR). The resultant fluorescently-labeled ligation products are detected on a universal array enabling simultaneous identification of the pathogens. The assay was evaluated on 32 different isolates associated with VHF (ebolavirus, marburgvirus, Crimean Congo hemorrhagic fever virus, Lassa fever virus, Rift Valley fever virus, Dengue virus, and Yellow fever virus) as well as variola virus and vaccinia virus (the agent of smallpox and its vaccine strain, respectively). The assay was able to detect all viruses tested, including 8 sequences representative of different variola virus strains from the CDC repository. It does not cross react with other emerging zoonoses such as monkeypox virus or cowpox virus, or six flaviviruses tested (St. Louis encephalitis virus, Murray Valley encephalitis virus, Powassan virus, Tick-borne encephalitis virus, West Nile virus and Japanese encephalitis virus).
Assuntos
Febres Hemorrágicas Virais/diagnóstico , Reação em Cadeia da Polimerase Multiplex/métodos , Varíola/diagnóstico , Vírus da Varíola/isolamento & purificação , Vírus/isolamento & purificação , Febres Hemorrágicas Virais/virologia , Humanos , Varíola/virologiaRESUMO
Monkeypox virus (MPXV) infection of the prairie dog is valuable to studying systemic orthopoxvirus disease. To further characterize differences in MPXV clade pathogenesis, groups of prairie dogs were intranasally infected (8 × 10(3) p.f.u.) with Congo Basin (CB) or West African (WA) MPXV, and 28 tissues were harvested on days 2, 4, 6, 9, 12, 17, and 24 postinfection. Samples were evaluated for the presence of virus and gross and microscopic lesions. Virus was recovered from nasal mucosa, oropharyngeal lymph nodes, and spleen earlier in CB challenged animals (day 4) than WA challenged animals (day 6). For both groups, primary viremia (indicated by viral DNA) was seen on days 6-9 through day 17. CB MPXV spread more rapidly, accumulated to greater levels, and caused greater morbidity in animals compared to WA MPXV. Histopathology and immunohistochemistry (IHC) findings, however, were similar. Two animals that succumbed to disease demonstrated abundant viral antigen in all organs tested, except for brain. Dual-IHC staining of select liver and spleen sections showed that apoptotic cells (identified by TUNEL) tended to colocalize with poxvirus antigen. Interestingly splenocytes were labelled positive for apoptosis more often than hepatocytes in both MPXV groups. These findings allow for further characterization of differences between MPXV clade pathogenesis, including identifying sites that are important during early viral replication and cellular response to viral infection.
Assuntos
DNA Viral/genética , Monkeypox virus/genética , Mpox/virologia , Replicação Viral/genética , Animais , DNA Viral/sangue , Modelos Animais de Doenças , Cinética , Fígado/virologia , Linfonodos/virologia , Mpox/sangue , Mpox/genética , Mpox/patologia , Monkeypox virus/patogenicidade , Mucosa Nasal/virologia , Filogenia , Sciuridae/sangue , Sciuridae/genética , Sciuridae/virologia , Baço/virologiaRESUMO
The ever-increasing bacterial resistance to clinical antibiotics is making many drugs ineffective and creating significant treatment gaps. This can be only circumvented by the discovery of antibiotics with new mechanisms of action. We report here the identification of a new tetramic acid, ascosetin, from an Ascomycete using the Staphylococcus aureus fitness test screening method. The structure was elucidated by spectroscopic methods including 2D NMR and HRMS. Relative stereochemistry was determined by ROESY and absolute configuration was deduced by comparative CD spectroscopy. Ascosetin inhibited bacterial growth with 2-16 µg ml(-1) MIC values against Gram-positive strains including methicillin-resistant S. aureus. It also inhibited the growth of Haemophilus influenzae with a MIC value of 8 µg ml(-1). It inhibited DNA, RNA, protein and lipid synthesis with similar IC50 values, suggesting a lack of specificity; however, it produced neither bacterial membrane nor red blood cell lysis. It showed selectivity for bacterial growth inhibition compared with fungal but not mammalian cells. The isolation, structure and biological activity of ascosetin have been detailed here.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Pirrolidinonas/química , Pirrolidinonas/farmacologia , Antibacterianos/isolamento & purificação , Ascomicetos/efeitos dos fármacos , Haemophilus influenzae/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Conformação Molecular , Pirrolidinonas/isolamento & purificação , Staphylococcus aureus/efeitos dos fármacosRESUMO
Since the eradication of Smallpox, researchers have attempted to study Orthopoxvirus pathogenesis and immunity in animal models in order to correlate results human smallpox. A solely human pathogen, Orthopoxvirus variola fails to produce authentic smallpox illness in any other animal species tested to date. In 2003, an outbreak in the USA of Orthopoxvirus monkeypox, revealed the susceptibility of the North American black-tailed prairie dog (Cynomys ludovicianus) to infection and fulminate disease. Prairie dogs infected with Orthopoxvirus monkeypox present with a clinical scenario similar to ordinary smallpox, including prodrome, rash, and high mortality. This study examines if Black-tailed prairie dogs can become infected with O. variola and serve as a surrogate model for the study of human smallpox disease. Substantive evidence of infection is found in immunological seroconversion of animals to either intranasal or intradermal challenges with O. variola, but in the absence of overt illness.
Assuntos
Modelos Animais de Doenças , Orthopoxvirus/patogenicidade , Sciuridae/virologia , Varíola/patologia , Animais , Anticorpos Antivirais/sangue , Feminino , Humanos , Imunidade , Masculino , Orthopoxvirus/genética , Orthopoxvirus/imunologia , Infecções por Poxviridae/imunologia , Infecções por Poxviridae/patologia , Varíola/imunologia , Varíola/virologiaRESUMO
In the spring of 2006, four human cases of parapoxvirus infections in Missouri residents were reported to the Centers for Disease Control and Prevention (CDC), two of which were initially diagnosed as cutaneous anthrax. This investigation was conducted to determine the level of recognition of zoonotic parapoxvirus infections and prevention measures, the degree to which veterinarians may be consulted on human infections and what forces were behind this perceived increase in reported infections. Interviews were conducted and clinical and environmental sampling was performed. Swab and scab specimens were analyzed by real-time polymerase chain reaction (PCR), whereas serum specimens were evaluated for parapoxvirus antibodies. Three case patients were found to have fed ill juvenile animals without using gloves. Forty-six percent of veterinarians reported having been consulted regarding suspected human orf infections. Orf virus DNA was detected from five of 25 asymptomatic sheep. Analysis of extracellular envelope gene sequences indicated that sheep and goat isolates clustered in a species-preferential fashion. Parapoxvirus infections are common in Missouri ruminants and their handlers. Infected persons often do not seek medical care; some may seek advice from veterinarians rather than physicians. The initial perception of increased incidence in Missouri may have arisen from a reporting artifact stemming from heightened concern about anthrax. Asymptomatic parapoxvirus infections in livestock may be common and further investigation warranted.