RESUMO
Eighty-nine T4-like phages from our phage collection were tested against four collections of childhood diarrhoea-associated Escherichia coli isolates representing different geographical origins (Mexico versusâ Bangladesh), serotypes (69 O, 27 H serotypes), pathotypes (ETEC, EPEC, EIEC, EAEC, VTEC, Shigella), epidemiological settings (community and hospitalized diarrhoea) and years of isolation. With a cocktail consisting of 3 to 14 T4-like phages, we achieved 54% to 69% coverage against predominantly EPEC isolates from Mexico, 30% to 53% against mostly ETEC isolates from a prospective survey in Bangladesh, 24% to 61% against a mixture of pathotypes isolated from hospitalized children in Bangladesh, and 60% coverage against Shigella isolates. In comparison a commercial Russian phage cocktail containing a complex mixture of many different genera of coliphages showed 19%, 33%, 50% and 90% coverage, respectively, against the four above-mentioned collections. Few O serotype-specific phages and no broad-host range phages were detected in our T4-like phage collection. Interference phenomena between the phage isolates were observed when constituting larger phage cocktails. Since the coverage of a given T4-like phage cocktail differed with geographical area and epidemiological setting, a phage composition adapted to a local situation is needed for phage therapy approaches against E. coli pathogens.
Assuntos
Colífagos/fisiologia , Diarreia/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/virologia , Especificidade de Hospedeiro , Bangladesh , Terapia Biológica/métodos , Colífagos/crescimento & desenvolvimento , Disenteria Bacilar/microbiologia , Escherichia coli/classificação , Escherichia coli/isolamento & purificação , Humanos , México , Shigella/isolamento & purificação , Shigella/virologia , Interferência ViralRESUMO
Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003-2010 to study the diversity of begomoviruses found in tomato, potato, and cucurbits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten begomovirus isolates were cloned from infected samples and identified as belonging to the species ToLCNDV. A total of 44 % of the samples showed association of betasatellites, with CLCuMuB and LuLDB being the most frequent. The ToLCNDV cloned component DNA A and DNA B were agroinoculated on Nicotiana benthamiana and tomato (Solanum lycopersicum) plants with or without betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored by real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with betasatellites showed enhanced symptom severity in both N. benthamiana and tomato, as well as increases in helper viral DNA A and DNA B levels. The DNA B and betasatellites acted antagonistically to each other, so that the level of DNA B was 16-fold greater in the presence of betasatellites, while accumulation of betasatellites, CLCuMuB and LuLDB, were reduced by 60 % in the presence of DNA B. DNA B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas betasatellite-mediated leaf abnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will be a good biotechnological tool in resistance breeding program.
Assuntos
Begomovirus/crescimento & desenvolvimento , Begomovirus/genética , DNA Satélite/genética , Vírus Auxiliares/crescimento & desenvolvimento , Doenças das Plantas/virologia , Interferência Viral , Begomovirus/isolamento & purificação , Cucurbita/virologia , DNA Viral/biossíntese , Variação Genética , Genoma Viral , Solanum lycopersicum/virologia , Folhas de Planta/virologia , Reação em Cadeia da Polimerase em Tempo Real , Solanum tuberosum/virologia , Nicotiana/virologiaRESUMO
Three tetravalent vaccine (TV) formulations of previously described monovalent dengue (DEN) virus vaccine candidates were compared to a tetravalent formulation of wild-type DEN viruses (T-wt) for replication in SCID mice transplanted with human liver cells (SCID-HuH-7) or for replication and immunogenicity in rhesus monkeys. TV-1 consists of recombinant DEN1, -2, -3, and -4, each with a 30-nucleotide deletion in the 3' untranslated region (Delta30). TV-2 consists of rDEN1Delta30, rDEN4Delta30, and two antigenic chimeric viruses, rDEN2/4Delta30 and rDEN3/4Delta30, both also bearing the Delta30 mutation. TV-3 consists of rDEN1Delta30, rDEN2Delta30, rDEN4Delta30, and a 10-fold higher dose of rDEN3/4Delta30. TV-1 and TV-2 were attenuated in SCID-HuH-7 mice with minimal interference in replication among the virus components. TV-1, -2, and -3 were attenuated in rhesus monkeys as measured by duration and peak of viremia. Each monkey immunized with TV-1 and TV-3 seroconverted to the four DEN components by day 28 with neutralization titers ranging from 1:52 to 1:273 and 1:59 to 1:144 for TV-1 and TV-3, respectively. TV-2 induced low antibody titers to DEN2 and DEN3, but a booster immunization after 4 months increased the neutralizing antibody titers to greater than 1:100 against each serotype and elicited broad neutralizing activity against 19 of 20 DEN subtypes. A single dose of TV-2 induced protection against wild-type DEN1, DEN3, and DEN4 challenge, but not DEN2. However, two doses of TV-2 or TV-3 induced protection against DEN2 challenge. Two tetravalent formulations, TV-2 and TV-3, possess properties of a successful DEN vaccine and can be considered for evaluation in clinical trials.
Assuntos
Anticorpos Antivirais/biossíntese , Vírus da Dengue/imunologia , Dengue/prevenção & controle , Vacinas Virais/imunologia , Regiões 3' não Traduzidas/genética , Animais , Reações Cruzadas , Vírus da Dengue/classificação , Vírus da Dengue/genética , Esquema de Medicação , Avaliação Pré-Clínica de Medicamentos , Humanos , Imunização Secundária , Macaca mulatta , Camundongos , Camundongos SCID , Vacinação , Vacinas Combinadas/administração & dosagem , Vacinas Combinadas/imunologia , Vacinas Sintéticas/imunologia , Interferência Viral , Vacinas Virais/administração & dosagem , Vacinas Virais/classificação , Replicação ViralRESUMO
Genetic and receptor interference data have indicated the presence of one or more cellular receptors for subgroup B, D, and E avian leukosis viruses (ALV) encoded by the s1 allele of the chicken tvb locus. Despite the prediction that these viruses use the same receptor, they exhibit a nonreciprocal receptor interference pattern: ALV-B and ALV-D can interfere with infection by all three viral subgroups, but ALV-E only interferes with infection by subgroup E viruses. We identified a tvb(s1) cDNA clone which encodes a tumor necrosis factor receptor-related receptor for ALV-B, -D, and -E. The nonreciprocal receptor interference pattern was reconstituted in transfected human 293 cells by coexpressing the cloned receptor with the envelope (Env) proteins of either ALV-B or ALV-E. This pattern of interference was also observed when soluble ALV surface (SU)-immunoglobulin fusion proteins were bound to this cellular receptor before viral challenge. These data demonstrate that viral Env-receptor interactions can account for the nonreciprocal interference between ALV subgroups B, D, and E. Furthermore, they indicate that a single chicken gene located at tvb(s1) encodes receptors for these three viral subgroups. The TVB(S1) protein differs exclusively at residue 62 from the published subgroup B- and D-specific receptor, encoded by the s3 allele of tvb. Residue 62 is a cysteine in TVB(S1) but is a serine in TVB(S3), giving TVB(S1) an even number of cysteines in the extracellular domain. We present evidence for a disulfide bond requirement in TVB(S1) for ALV-E infection but not for ALV-B infection. Thus, ALV-B and ALV-E interact in fundamentally different ways with this shared receptor, a finding that may account for the observed biological differences between these two ALV subgroups.
Assuntos
Vírus da Leucose Aviária/fisiologia , Cisteína/química , Receptores do Fator de Necrose Tumoral/metabolismo , Receptores Virais/metabolismo , Sequência de Aminoácidos , Animais , Vírus da Leucose Aviária/classificação , Vírus da Leucose Aviária/genética , Vírus da Leucose Aviária/metabolismo , Linhagem Celular , Galinhas , Clonagem Molecular , DNA Complementar/genética , Humanos , Dados de Sequência Molecular , Mutação , Receptores do Fator de Necrose Tumoral/química , Receptores do Fator de Necrose Tumoral/genética , Receptores Virais/química , Receptores Virais/genética , Análise de Sequência de DNA , Interferência Viral , Proteínas Virais/metabolismoRESUMO
Plants of bean (Phaseolus vulgaris) inoculated first on one primary leaf with strain NY15 of bean common mosaic virus, as inducer, and after three days, on the opposite leaf, with the strain NL3 of bean black root virus, as challenger, did not show systemic necrosis characteristic of the latter strain. This interference phenomenon was studied by determining the amount, distribution and localization of both strains in the part of stem between primary leaves and first trifoliolate leaf in both challenge-inoculated and singly inoculated (control) plants. In dot-blot immunoassay, NL3 was detected seven days after its inoculation as challenger, whereas in control plants its presence was established on day four. Immunostained thick sections revealed a large accumulation of NL3 antigen on day eight in both phloem and cambium, but not yet in the xylem and cortex, contrasted with the controls. In immunogold-silver stained semi-thin sections, most of the NL3 label was present in the companion cells and other phloem parenchyma cells, while in the control plants this virus was also present in xylem vessels and xylem parenchyma cells. Inducer strain NY15 was abundantly present in practically all the cells, including xylem vessels, from day two after challenge inoculation onwards. It is concluded that inducer strain NY15 hampers transport of NL3 to, and its spread in, the stem and prevents the latter strain from exerting its deleterious influence on the water conducting elements.
Assuntos
Fabaceae/virologia , Doenças das Plantas , Plantas Medicinais , Potyvirus/fisiologia , Interferência Viral , Técnicas Imunológicas , Caules de Planta/virologiaRESUMO
Potato virus X (PVX) and potato virus Y (PVY) infection in potato may result in the loss of certification of seed potatoes and affect quality and yield of potatoes in commercial production. We transformed a major commercial cultivar of potato, Russet Burbank, with the coat protein genes of PVX and PVY. Transgenic plants that expressed both CP genes were resistant to infection by PVX and PVY by mechanical inoculation. One line was also resistant when PVY was inoculated with viruliferous green peach aphids. These experiments demonstrate that CP protection is effective against mixed infection by two different viruses and against mechanical and aphid transmission of PVY.
Assuntos
Engenharia Genética , Doenças das Plantas , Vírus de Plantas/genética , Solanum tuberosum/genética , Sequência de Aminoácidos , Animais , Afídeos , Sequência de Bases , Capsídeo/genética , Imunidade Inata , Insetos Vetores , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas Recombinantes/genética , Solanum tuberosum/microbiologia , Interferência ViralRESUMO
The paper is a review of researches done at the "Stefan S. Nicolau" Institute of Virology, in Bucharest, the last five years, in the antiviral chemotherapy field, as well as of the chemotherapeutical implications of studies conducted about other aspects of virology.
Assuntos
Academias e Institutos , Antivirais/uso terapêutico , Virologia , Animais , Avaliação Pré-Clínica de Medicamentos , Extratos Vegetais/uso terapêutico , Pesquisa , Romênia , Interferência Viral/efeitos dos fármacosRESUMO
Plant viral genomes are relatively small and in the past decade many have been characterized at the molecular level. This has prompted research into the development of virus resistance based on interference with the viral multiplication cycle by teh introduction of viral sequences into the plant genome. Several strategies have been tested. The most successful one so far involves the constitutive expression of the coat protein gene of the virus against which resistance is desired. In this review we describe progress made in engineering virus resistance into potato, an important agricultural crop. To this end the molecular structure of the potato viruses X and Y and leafroll is discussed as well as the introduction of resistance against potato virus X into potato. In addition, we address the question of preservation of cultivar-specific characteristics, an important prerequisite for commercial application. Finally, recent investigations for alternative forms of virus resistance are described against the background of the results of coat protein-mediated protection.
Assuntos
Vírus de Plantas/genética , Plantas/microbiologia , Capsídeo/genética , Engenharia Genética , Plantas/genética , RNA/genética , RNA Antissenso/genética , RNA Satélite , RNA Viral/genética , Solanum tuberosum/genética , Solanum tuberosum/microbiologia , Interferência Viral/genéticaRESUMO
The chromatographic properties of human interferon-alpha from Namalwa lymphoblastoid cells on Sephadex G-75 are described. The interferons are separated into two groups of four, with apparent molecular weights 19050 and 22000. Some of the latter form dimers at high concentrations. Fractions containing interferon were studied by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. Seven of the components had apparent molecular weights in this system, after reduction, of between 18400 and 20900: one component is probably glycosylated and has an apparent molecular weight of 27500. Amino acid sequences of peptides derived from interferon mixtures were determined and are related to published sequences deduced from the nucleotide sequences of cloned complementary DNA coding for interferon-alpha. The results show that the major interferon-alpha species isolated from Namalwa cells do not undergo C-terminal processing. Amino acid analyses of peptides are presented in Supplementary Publication SUP 50117 (28 pages), which has been deposited with the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1981) 193, 5.
Assuntos
Interferon Tipo I/metabolismo , Linfócitos/metabolismo , Sequência de Aminoácidos , Aminoácidos/análise , Linhagem Celular , Cromatografia em Gel , Eletroforese em Gel de Poliacrilamida , Humanos , Fragmentos de Peptídeos/análise , Interferência ViralAssuntos
Poliovirus/crescimento & desenvolvimento , RNA Mensageiro/metabolismo , RNA Viral/metabolismo , Vírus da Estomatite Vesicular Indiana/metabolismo , Proteínas Virais/biossíntese , Sistema Livre de Células , Células HeLa , Biossíntese Peptídica , Extratos Vegetais , Biossíntese de Proteínas , Triticum , Interferência Viral , Replicação ViralAssuntos
Antivirais/uso terapêutico , Influenza Humana/tratamento farmacológico , Amantadina/administração & dosagem , Amantadina/efeitos adversos , Amantadina/análogos & derivados , Amantadina/uso terapêutico , Animais , Avaliação de Medicamentos , Humanos , Indutores de Interferon/uso terapêutico , Interferons/uso terapêutico , Neuraminidase/antagonistas & inibidores , Pneumonia/tratamento farmacológico , Pneumonia Viral/tratamento farmacológico , Ribavirina/uso terapêutico , Terpenos/uso terapêutico , Vacinação , Interferência ViralRESUMO
Nonspecific enhancers of resistance may include (1) viral interference, (2) interferon, (3) interferon inducers, (4) bacterial interference, (5) bacterial products such as Coley's "toxins," endotoxins, or staphylococcal, BCG, and Corynebacterium parvum vaccines, (6) transfer factor, and (7) well-defined chemicals such as dinitrochlorbenzene, levamisole, and vitamin C. These are discussed only as they have been applied to man to learn whether or not they have enhanced his ability to resist infections and growth of tumors. Preliminary studies suggest that a variety of relatively safe and effective nonspecific enhancers may soon be available for clinical use.
Assuntos
Adjuvantes Imunológicos/farmacologia , Imunidade/efeitos dos fármacos , Animais , Ácido Ascórbico/uso terapêutico , Vacina BCG/uso terapêutico , Bactérias/metabolismo , Dinitroclorobenzeno/uso terapêutico , Endotoxinas/fisiologia , Humanos , Imunidade Celular/efeitos dos fármacos , Indutores de Interferon/farmacologia , Interferons/uso terapêutico , Levamisol/uso terapêutico , Melanoma/tratamento farmacológico , Camundongos , Propionibacterium acnes/imunologia , Ratos , Infecções Respiratórias/terapia , Neoplasias Cutâneas/tratamento farmacológico , Vacinas Antiestafilocócicas/uso terapêutico , Fator de Transferência/uso terapêutico , Interferência ViralRESUMO
The frequency of naturally occurring transplacental infection of swine with porcine parvovirus (PPV) and one of the possible consequences of such infection--the presence of PPV in cell cultures prepared from fetal tissues--were investigated. Transplacental infection was indicated by the presence of high titers of hemagglutination inhibiting (HI) antibody for PPV in serums of 0-day-old, hysterectomy-derived, colostrum-deprived pigs of 3 of 82 litters. All letters were farm-raised dams. Moreover, cell cultures prepared from 3 of 49 lots of fetal porcine kidneys (FPK) collected from an abattoir during an interval of 14 months were found contaminated with PPV. Because each lot was usually comprised of kidneys from 2 litters, the latter finding suggests that 3 of approximately 98 litters were infected. Prior infection of FPK cell cultures with PPV resulted in only slight interference of replication of other selected viruses; i.e., porcine enterovirus (PEV), pseudorabies virus (PRV), vesicular stomatitis virus (VSV), and hemagglutinating encephalomyelitis virus (HEV). Moreover, PPV and HEV were propagated in the same cell cultures during 5 serial passages of the viruses. In contrast, when copropagation of PPV and VSV was attempted, PPV was not detected after the 2nd serial passage.
Assuntos
Doenças Fetais/veterinária , Troca Materno-Fetal , Parvoviridae , Doenças dos Suínos/etiologia , Viroses/veterinária , Animais , Células Cultivadas , Colostro/imunologia , Meios de Cultura , Enterovirus/crescimento & desenvolvimento , Feminino , Doenças Fetais/etiologia , Doenças Fetais/imunologia , Herpesvirus Suídeo 1/crescimento & desenvolvimento , Rim , Parvoviridae/crescimento & desenvolvimento , Parvoviridae/imunologia , Gravidez , Suínos , Doenças dos Suínos/imunologia , Vírus da Estomatite Vesicular Indiana/crescimento & desenvolvimento , Interferência Viral , Viroses/etiologia , Viroses/imunologia , Replicação ViralRESUMO
The infectious ribonucleic acid (RNA) of potato spindle tuber virus (PSTV) can be separated by hydroxyapatite chromatography from double-stranded RNA detectable in low amounts in both infected and uninfected plant tissue extracts. The chromatographic behavior of ribonuclease-sensitive PSTV RNA resembles that of transfer RNA.
Assuntos
Vírus de Plantas , Plantas Comestíveis , RNA Viral/isolamento & purificação , RNA/isolamento & purificação , Animais , Cromatografia , Técnicas de Cultura , Desoxirribonucleases , Hidroxiapatitas , Rim , Métodos , Doenças das Plantas , Extratos Vegetais , Vírus de Plantas/análise , Vírus de Plantas/patogenicidade , RNA Viral/análise , RNA Viral/farmacologia , Coelhos , Ribonucleases , Vírus da Estomatite Vesicular Indiana/crescimento & desenvolvimento , Interferência ViralRESUMO
PIP: Field observations are reported which support an assumption that human breast milk acts benefically through induced host resistance to infection. Though the mechanisms of this induced host resistance to infection are not clearly understood, this article suggests the following factors as important: specific antibodies to infectious agents, influences stimulating or inhibiting certain intestinal microorganisms, and nonspecific antimicrobial factors. Immunoglobulins are present in human milk, with IgA representing the most abundant; the role of complement and immunoglobulin in induction of resistance to infection is well-known. Since all immunoglobulins have antibody activity, it is conceivable that immunoglobulins provide the material for antibodies to various etiological agents; for example, serum IgA contains all types of antibodies; serum IgG has a wide variety of antibodies to viruses, rickettsiae, protozoa, H antigens of Salmonella, and bacterial antitoxins and incomplete Rh antibodies; and the IgM fraction contains antibodies to O antigens of Enterobacteriacae, Rh agglutinins, and syphilis reagins. Another aspect of human milk as an inducer of host resistance is the bifidus factor which promotes development of characteristic microflora; since the bifidobacteria metabolize a variety of sugars, producing large amounts of acetic and lactic acids and trace amounts of formic and succinic acids, these organisms affect pH and, hence, certain resistance factors. Other factors present in milk include lysozyme (muramidase), complement, interferon, and immune cells, all of which promote host resistance to infection.^ieng
Assuntos
Leite Humano/imunologia , Anticorpos/análise , Especificidade de Anticorpos , Antígenos de Bactérias , Pré-Escolar , Colostro/análise , Colostro/imunologia , Proteínas do Sistema Complemento/análise , Enterobacteriaceae/imunologia , Enterovirus/imunologia , Escherichia coli/isolamento & purificação , Fezes/microbiologia , Feminino , Humanos , Imunidade Materno-Adquirida , Imunoglobulina A/análise , Imunoglobulina D/análise , Imunoglobulina G/análise , Imunoglobulina M/análise , Lactente , Recém-Nascido , Controle de Infecções , Intestinos/microbiologia , Lactação , Lactobacillus/isolamento & purificação , Leite Humano/análise , Poliovirus/imunologia , Gravidez , Interferência ViralAssuntos
Fenótipo , Vírus do Mosaico do Tabaco/crescimento & desenvolvimento , Soluções Tampão , Genética Microbiana , Soros Imunes , Mutação , Testes de Neutralização , Doenças das Plantas , Extratos Vegetais , Vírus de Plantas/crescimento & desenvolvimento , Vírus de Plantas/imunologia , Vírus de Plantas/patogenicidade , Plantas Tóxicas , RNA Viral , Temperatura , Nicotiana , Vírus do Mosaico do Tabaco/imunologia , Vírus do Mosaico do Tabaco/patogenicidade , Ultracentrifugação , Interferência Viral , Proteínas Virais , Replicação ViralRESUMO
Crowell, Richard L. (Hahnemann Medical College, Philadelphia, Pa.). Specific cell-surface alteration by enteroviruses as reflected by viral-attachment interference. J. Bacteriol. 91:198-204. 1966.-Exposure of HeLa cells to high levels of coxsackievirus B3 produced cells which were refractory to attachment of coxsackievirus B1, whereas poliovirus T2 attached normally. Under similar conditions, poliovirus T2 was found to interfere with the attachment of poliovirus T1 to HeLa cells without affecting the attachment rate of coxsackievirus B3. The data confirm earlier findings that the receptor sites on HeLa cells, which bind members of group B coxsackieviruses, are distinct from those for polioviruses. Quantitatively, coxsackieviruses B1 and B3 were found to be mutually exclusive in the attachment interference assay to suggest that they compete for the same receptors on the HeLa cell surface. The finding that input multiplicities of B3 virus which exceeded 500 saturated the homologous viral receptors of HeLa cells was unexpected, but was consistent with the results of interference assays. Excessive amounts of input virus did not, however, inhibit eclipse of homologous cell-associated virus. Attachment interference between enteroviruses occurred even though the interfering virus was eclipsed prior to addition of challenge virus. The finding that enterovirus attachment interference was reversible with acid pH suggested that attachment and eclipse of enterovirus does not result in a permanent alteration of the cell membrane and that these events occur at the cell surface.